State of Sanctuary Resources
This section provides summaries of the conditions and trends within four resource areas: water, habitat, living resources, and maritime archaeological resources. For each, sanctuary staff and selected outside experts considered a series of questions about each resource area. The set of questions is derived from the Office of National Marine Sanctuaries' mission, and a system-wide monitoring framework (NMSP 2004) developed to ensure the timely flow of data and information to those responsible for managing and protecting resources in the ocean and coastal zone, and to those that use, depend on, and study the ecosystems encompassed by the sanctuaries. The questions address information needs that are common to nearly all sanctuaries throughout the sanctuary system. Appendix A (Rating Scheme for System-Wide Monitoring Questions) clarifies the set of questions and presents statements that were used to judge the status and assign a corresponding color code on a scale from "good" to "poor." These statements are customized for each question. In addition, the following options are available for all questions: “N/A” –the question does not apply; and “undetermined” – resource status is undetermined. In addition, symbols are used to indicate trends: “ ▲” – conditions appear to be improving; “▬” – conditions do not appear to be changing; “ ▼” –conditions appear to be declining; and “?” – the trend is undetermined.
This section of the report provides answers to the set of questions. Despite a large diversity in habitat types and communities within the Florida Keys sanctuary, a single, sanctuary-wide status and trend rating is given for each question. Although the ratings are generalized for the entire sanctuary, text found in the following section provides a detailed description of the basis for judgment for each question, and may include recognition and description of any conditions that are not consistent with the rating. Answers are supported by specific examples of data, investigations, monitoring and observations, and the basis for judgment is provided in the text and summarized in the table for each resource area. Where published or additional information exists, the reader is provided with appropriate references and Web links.
Judging an ecosystem as having "integrity" implies the relative wholeness of ecosystem structure and function, along with the spatial and temporal variability inherent in these characteristics, as determined by the ecosystem's natural evolutionary history. Ecosystem integrity is reflected in the system's ability to produce and maintain adaptive biotic elements. Fluctuations of a system's natural characteristics, including abiotic drivers, biotic composition, complex relationships, and functional processes and redundancies are unaltered and are either likely to persist or be regained following natural disturbance.
Water
The following information provides an assessment by sanctuary staff and experts in the field of the status and trends pertaining to the current state of water quality in Florida Keys National Marine Sanctuary:
1. Are specific or multiple stressors, including changing oceanographic and atmospheric conditions, affecting water quality and how are they changing?
An increasing number of stressors to water quality over the last several decades may cause measurable but not severe declines in living resources and habitats. For this reason, the rating for this question is "fair." The trend is rated as "declining" because stressors affecting water quality in the sanctuary have been increasing since its establishment, and the predicted effects of global climate change are likely to exacerbate conditions via changes in storm frequency and intensity, upwelling frequency and duration, changing variability of seawater temperature (Figure 22), sea level rise (Figure 23), and other changes to oceanographic patterns and ocean chemistry.
Climate and weather affect water quality through winds and storms, precipitation, evaporation, surface water input, sea level and tides, and "boundary" currents (e.g., Loop and Florida Currents), all of which play an important role in the ecosystem dynamics of Florida Bay and the sanctuary. During the last half-century, regional water management practices have evolved to temper the way climate and weather affect human health and well-being. However, water management during this time has also had direct and indirect impacts on nearshore water quality within the sanctuary. In the latter third of the 20th century, it was recognized that flood control modifications to the drainage of fresh water in the south Florida region resulted in serious environmental effects due to altered water delivery into the surrounding estuarine system, specifically Florida Bay. Although some freshwater flow is currently being restored (via the Comprehensive Everglades Restoration Plan, as approved and amended in the Water Resources Development Act of 2000), it can never be restored to its native state due to the needs of the surrounding human population.
2. What is the eutrophic condition of sanctuary waters and how is it changing?
There is no evidence of eutrophication within the Florida Keys sanctuary or the surrounding waters. For this reason, this question is rated "good" and "not changing." Chlorophyll levels spanning seven years (1997-2004) were summarized and chlorophyll in the sanctuary never approached values that would indicate eutrophication (Stumpf et al. 2005). Monthly estimates of chlorophyll-a in recent years (2004-present) demonstrate similar patterns (Florida Keys sanctuary, unpubl. data). Levels of chlorophyll-a concentrations and the absence of harmful algal blooms, as measured from samples taken within the sanctuary (California Department of Health Services, monthly reports), lead sanctuary scientists to believe that eutrophication is not a problem within Florida Keys sanctuary, and conditions appear stable.
Depending on the geographic scale at which water quality within the sanctuary is considered, monitoring results show there are distinct regional and smaller-scale patterns in water chemistry, some of which are addressed in Question 2. However, in response to this question, we describe and qualify the state of water quality stressors in the sanctuary as a whole, as opposed to separating the various geographic and hydrographic areas of the Florida Keys and their individual states. Detailed water quality information for specific areas of the sanctuary can be found in several references (MACTEC 2003, Hunt and Nuttle 2007, Boyer and Briceño 2009). Generally, we know that the individual "state" of residential canal water tends to have low dissolved oxygen levels, high hydrogen sulfide content, and higher potential for nutrient loading in comparison to the adjacent nearshore waters that have better flushing and flow regimes. In turn, areas of nearshore waters may have eutrophic signals that attenuate further offshore where regional water flows have more substantial influences. The sanctuary is directly influenced by the Florida Current, the Gulf of Mexico Loop Current, inshore currents of the Southwest Florida Shelf (Shelf), discharge from the Everglades through the Shark River Slough, and by tidal exchange with both Florida Bay and Biscayne Bay (Lee et al. 1994, Lee et al. 2002). Thus, not all influences on water quality originate from sources within the Florida Keys. Likewise, Boyer and Briceño 2009 point out that trends observed at smaller (local) scales may also occur across the whole region but at more damped amplitudes. This spatial autocorrelation in water quality is an inherent property of highly interconnected systems such as coastal and estuarine ecosystems driven by similar hydrological and climatological forcings. There have been large changes in the sanctuary's water quality over time, and some sustained monotonic trends have been observed over the last 15 years. However, trend analysis is limited to the window of observation; trends may change, or even reverse, with additional data collection (Wagner et al. 2008, Boyer and Briceño 2009).
Finally, during the last 100 years, the Florida Keys island chain has been physically altered to accommodate passenger trains and vehicles by filling in island passes to create highways and railroad beds. This alteration has permanently affected the flushing dynamics (e.g., oceanographic processes) between the four prominent water bodies adjacent to the sanctuary. With the exception of new bridge construction in upper Key Largo, where flow between water bodies is being enhanced, most altered flow in the Keys is unlikely to change in the immediate future.
2. What is the eutrophic condition of sanctuary waters and how is it changing?
Water quality in the sanctuary is influenced by waters emanating from freshwater and estuarine habitats near the Florida Everglades, shallow nearshore areas, and deeper (>100 m) offshore areas. Distinguishing internal from external sources of nutrients in the sanctuary is a difficult task, and the finer discrimination of internal sources from external natural and anthropogenic inputs is even more difficult. Regardless of the source(s), enough evidence exists to rate this question as "fair/poor" because selected conditions have caused or are likely to cause severe declines in some but not all living resources and habitats. The trend is rated as "not changing" because results of the sanctuary's long-term water quality monitoring program do not suggest eutrophic conditions are changing at large spatial scales at this time (Boyer and Briceño 2009).
A large-scale water quality monitoring program was established in the sanctuary in 1995 and provides quarterly sampling of a suite of 18 variables at 155 stations in the sanctuary, extending from the southern boundary of Biscayne National Park to the Dry Tortugas. Several important results have been obtained from this project. First, elevated nitrate has been documented in the inshore waters of the Florida Keys (Figure 24) since the first sampling event in 1995 and continues to be a characteristic of the ecosystem. Interestingly, this nitrate gradient was not observed in a comparison transect from the Dry Tortugas (where there is minimal human impact), thus the nitrate distribution implies a localized, land-based source, which is diluted by lower-nutrient waters of the Atlantic Ocean. Sampling studies also show that there is a similar gradient in total organic carbon as well as a decrease in the variability of salinity moving offshore, further supporting the theory that the source is localized and land-based. There have been no reported trends in either total phosphorous or chlorophyll-a with distance from land. Second, the highest chlorophyll-a concentrations, which are indicative of phytoplankton in the water column, are present on the southwest Florida Shelf and diminish gradually towards the Marquesas and Dry Tortugas (Figure 25). Water with higher total phosphorus concentrations from the shelf is carried south along the southwest coast of Florida, where it fuels the phytoplankton blooms in the region (Boyer and Briceño 2009).
Generally, trends in most measured nutrient variables since 1995 show relative consistency from year to year, with some exhibiting seasonal variations. Overall,Boyer and Briceño 2009 (2009) found that there were statistically significant decreases in dissolved inorganic carbon, total organic nitrogen (except for increases in the Tortugas), total phosphorus, total organic carbon, and dissolved oxygen throughout the region. This is contrary to some of the trend analyses reported in previous years. Most of the important local anthropogenic inputs are regulated and controlled by management activities; other studies have shown that nutrients from shallow sewage injection wells may be leaking into nearshore surface waters (Corbett et al. 2000). There have been large changes in sanctuary water quality over time, and some sustained monotonic trends have been observed; however, trend analysis is limited to the window of observation, and trends may change, or even reverse, with additional data collection. Thus, when looking at what are perceived to be local trends it also seems to occur across the whole region but at more damped amplitudes (Boyer and Briceño 2009).
Large, persistent cyanobacterial blooms originating in Florida Bay have been associated with sponge die-offs (as well as seagrass die-offs) and the associated community dependent upon them (Butler et al. 1995, Fourqurean and Robblee 1999, Hunt and Nuttle 2007). These blooms are not necessarily triggered or sustained by a single change in nutrient load, but rather reflect a combination of multiple biotic and abiotic factors that contribute to their intensity and duration. Unfortunately, we do not have sufficient data at this time to predict cyanobacterial bloom initiation or longevity, thus there is a need to integrate existing biological, climatological, and oceanographic research efforts so that predictive models can be further developed and refined to support management decisions for control efforts.
It is clear that trends observed within the sanctuary are influenced by regional conditions outside the sanctuary boundaries (Boyer and Briceño 2009). Nutrients originating north of the sanctuary on the Gulf side of Florida may have increased the size and persistence of various harmful algal blooms (ranging from red tides to black-water events). As these phenomena have been correlated with fish kills and seagrass die-offs, their increasing geographic influence could put resources at risk that have not been so previously (including those on the ocean side of the Florida Keys).
3. Do sanctuary waters pose risks to human health and how are they changing?
Harmful algal blooms (e.g., red tides), fecal coliform and enterococci bacteria, and ciguatera fish poisoning have the potential to affect human health in the sanctuary, thus the rating for this question is "fair" because selected conditions have resulted in isolated human impacts, but evidence does not justify widespread or persistent concern. In addition, the trend is rated as "not changing" because there is no evidence to suggest conditions are changing at this time.
Depending on the geographic scale considered, some small patterns in human health emerge. However, for the purposes of this question, we describe and qualify the state of sanctuary waters on human health as a "whole," as opposed to separating the various geographic/hydrographic areas of the Florida Keys and their individual status. As outlined in Question 1, water quality in most residential canals is poor (small-scale, local) when compared to nearshore and oceanic waters (large-scale, regional). Thus swimming in residential canal water may pose risks to human health (e.g., result in gastroenteritis). The same is true for swimming in areas of residential canal outflows. In addition, during the "Swim Around Key West" event in 1999, 30% of swimmers reported at least one symptom of a waterborne disease and 20% reported two or more symptoms (Nobles et al. 2000). However, nearshore and offshore waters are not considered to pose risks to human health.
As described in the "Pressures" section of this document, harmful algal blooms (HABs) have increased in frequency within the last few decades (Harvell et al. 1999). Though no cases of human illness have been documented in association with the consumption of fish during Florida red tide blooms (Abbott et al. 2009b), fishes exposed to red tides can concentrate brevetoxin in their viscera, but levels in the muscle tissue do not suggest a health risk to humans. Notably, sanctuary waters had high concentrations of the microscopic alga that causes red tide on offshore reefs during the 2009 and 2010 red tide "seasons" (MEERA4), which is the first documented occurrence of this phenomenon.
Periodic swim advisories and warnings are issued by the Florida Department of Health due to the presence of pathogen indicators (enterococci and fecal coliform bacteria). High concentrations of these bacteria and viruses may indicate the presence of microorganisms that could cause gastrointestinal distress, disease, infections, or rashes in people swimming in nearshore waters (Nobles et al. 2000). Advisories and warnings are common at some locations in Monroe County, specifically at South and Higgs Beaches in Key West, which have the highest frequencies of warnings issued per beach since weekly testing began in 2003 (Figure 26). Swim advisories and warnings pertain to very specific areas and the nearshore waters adjacent to them. Therefore, the advisories reflect water quality conditions in specific areas and do not reflect risks to human health throughout the entire sanctuary.
Ciguatera fish poisoning (CFP) occurs throughout the tropical Pacific and the Caribbean. CFP is a reportable disease in Florida (Chapter 64D-3, Florida Administrative Code) (Abbott et al. 2009b). Reported CFP cases in Monroe County are rare, with the most recent case in 2006. However, it is well documented that certain fishes such as grouper, moray eel, jacks, kingfish, snapper, hogfish (Lachnolaimus maximus) and barracuda (Sphyraena barracuda) are more prone to be ciguatoxic due to their position in the food chain and large adult size (de Sylva 1994, Abbott et al. 2009a). While CFP is an issue regionally and has been reported locally in the Florida Keys, there is no evidence that the incidence of ciguatera is increasing in the sanctuary.
4. What are the levels of human activities that may influence water quality and how are they changing?
Water quality within the boundary of the sanctuary is affected by a combination of regional oceanographic patterns, climatology, and regional and localized anthropogenic influences. As discussed in the "Site History" and "Pressures" sections of this document, during the last century destructive activities (e.g., dredge and fill, untreated storm water, discharge of poorly treated sewage) have been widespread throughout the region, thus the rating for this question is "fair/poor" because many human activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem. However, the trend is rated as "improving" because management responses are addressing the widespread, pervasive problems, leaving issues that are more localized.
As stated previously, the degree to which human activities influence water quality depends on the scale under consideration. At smaller, localized scales, water quality in the Keys has been affected by the dredging of dead-end residential canals. Most of these canals have poor flushing because of the way they were constructed. Depending on wind and currents, these residential canals accumulate seagrass "wrack" which depletes dissolved oxygen during decomposition and increases the level of nutrients and hydrogen sulfide gas in the water. Hydrogen sulfide gas is toxic and residences near heavily polluted canals may be at risk. Furthermore, residential canals receive additional nutrient and chemical loading via stormwater runoff. At larger, regional scales, island passes that were filled in to create highways and railroad beds have permanently altered the flushing dynamics (e.g., oceanographic processes) between the four prominent water bodies adjacent to the sanctuary.
In addition to the human activities stated in Question 1 (e.g., flood control modifications, runoff, highway/railroad construction), another that affects water quality is mosquito control. The Florida Keys are subtropical in climate and subject to mosquito-borne pathogens like West Nile virus, Dengue fever and viral encephalitis. Successful application of insecticides from both airborne platforms and vehicles is subject to climatological conditions. In the past, the Florida Keys Mosquito Control District used thermal fogging to apply pesticides (specifically adulticides). The pesticide was diluted with diesel oil and either passed through the engine of the plane or through a blower applicator mounted in the back of a truck. This delivery process produced a thick cloud of smoke easily observed by residents. It also produced a certain level of pollution due to the fumes of the diesel oil. Now the district uses ultra-low volume applications, in which a very small amount of pesticide is used to achieve the same results while eliminating pollution caused by the diesel oil carrier.
Nevertheless, though most insecticides are successfully delivered to their target, nearshore waters of the sanctuary are still susceptible to over-spraying, insecticide runoff, and sublethal and lethal effects on non-target organisms (i.e., other invertebrates that are harmed by the poisons used). The Florida Keys Mosquito Control District has a research program focused on basic and applied aspects of mosquito biology and control; however the impacts of mosquito spraying on non-target marine organisms need further research. The Fish and Wildlife Research Institute has conducted research that demonstrates that mosquito control pesticides are detrimental to queen conch (McIntyre et al. 2006, Glazer et al. 2008).
Water Status and Trends
Status: Good Good/Fair Fair Fair/Poor Poor Undet.
Trends:
▲ Conditions appear to be improving.
- Conditions do not appear to be changing.
▼ Conditions appear to be declining.
? Undeterminted trend.
N/A Question not applicable.
# |
Status |
Rating |
Basis For Judgement |
Description of Findings |
1. |
Stressors |
|
Large-scale changes in flushing dynamics over many decades have altered many aspects of water quality; nearshore problems related to runoff and other watershed stressors; localized problems related to infrastructure. |
Selected conditions may inhibit the development of assemblages and may cause measurable but not severe declines in living resources and habitats. |
2. |
Eutrophic Condition |
|
Long-term increase in inputs from land; large, persistent phytoplankton bloom events, many of which originate outside the sanctuary but enter and injure sanctuary resources. |
Selected conditions have caused or are likely to cause severe declines in some but not all living resources and habitats.
|
3. |
Human Health |
|
Rating is a general assessment of "all waters" of the sanctuary, knowing that in very specific locations, the rating could be as low as "poor." Increased frequency of HABs and periodic swim advisories. |
Selected conditions have resulted in isolated human impacts, but evidence does not justify widespread or persistent concern.
|
4. |
Human Activities |
|
Historically, destructive activities have been widespread throughout the Florida Keys, but many recent management actions are intended to reduce threats to water quality. |
Selected activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem.
|
Habitat
The following information provides an assessment by sanctuary staff and experts in the field of the status and trends pertaining to the current state of marine habitats in Florida Keys National Marine Sanctuary:
5. What is the abundance and distribution of major habitat types and how are they changing?
Generally, at larger spatial scales, nearshore habitats are still present in the geographic areas they occupied through the history of the sanctuary, which suggests the abundance and distribution of the coral, seagrass, and hard-bottom habitat types in the sanctuary have changed little over the last 20 years. With the exception of the water column realm, the major habitat types in the sanctuary are benthic and biogenic in nature and are defined by dominant fauna or flora: coral reefs, seagrass meadows, hard-bottom communities (a mix of hard corals, gorgonians and sponges), and mangrove habitats. In order to answer this question, the absolute "number" and the "geographic extent" of the major habitat types found in the sanctuary were examined. Questions 6, 9, 12, and 13 of this report will address the "health and condition" of these biogenic habitats. With this in mind, the response to this question is rated "good/fair" because selected habitat loss or alteration has taken place (principally due to nearshore development), precluding full development of living resource assemblages, but it is unlikely to cause substantial or persistent degradation in living resources or water quality. The trend is rated as "not changing" because there is no evidence to suggest that the conditions that affect the abundance and distribution of all habitat types are changing significantly.
During the 20th century, nearshore habitat alteration in the Florida Keys was extensive, with much of the physical alteration occurring from the 1950s through the 1970s to support the growing human population. During that period, many acres of tropical hardwood hammocks were cleared to provide land for housing and commercial development. The attractiveness of waterfront development prompted the creation of "fastland" through dredging and filling of mangrove forests and seagrass beds to construct networks of finger-fill residential canals. Approximately 50% of the historic mangrove habitat has been eliminated. More than 200 canals and access channels were dredged during that period (FDER 1987, Kruczynski and McManus 2002). Turbidity from the dredging and filling operations smothered adjacent areas of hard-bottom and seagrass habitats (MACTEC 2003).
The sanctuary encompasses over 2,800 square nautical miles and encompasses a majority of the archipelago of the Florida Keys. Recently, efforts have been made to accurately map the abundance and distribution of habitat types at a finer scale. In 1998, NOAA and the FWC's Fish and Wildlife Research Institute released habitat maps for the Florida Keys (Figure 27), representing the first large-scale effort to accurately map coral ecosystem habitats in the Florida Reef Tract, from Biscayne Bay to the Dry Tortugas (http://flkeysbenthicmaps.noaa.gov). The 1998 NOAA and FWC effort was a duplication of a 1970s effort to map the basic habitat of the Keys (Marszalek et al. 1977), but utilized more advanced technology. Habitats were delineated based on visual interpretation of 450 aerial photographs collected in 1991 to 1992 (FFWCC et al. 1998). The atlas was revised in 2000, but because it has large areas of unmapped seafloor, a new mapping effort is underway to address this shortcoming.
The sanctuary has also benefited from highly detailed bathymetric maps of portions of the Florida Reef Tract produced by partnerships between USGS, NASA, and theNPS (using LiDAR technology; http://ngom.usgs.gov/dsp/pubs/ofr/index.html) and from multi-beam sonar surveys performed by the NOAA ship Nancy Foster. In spite of these combined efforts, more than 50% of the sanctuary remains to be adequately mapped. As of 2009, a higher proportion of nearshore areas (< 150 feet in depth) were mapped in comparison to deeper areas, thus limiting the ability to quantitatively estimate the abundance and distribution of sanctuary.
6. What is the condition of biologically structured habitats and how is it changing?
Marine life depends on the integrity of its habitats, and that integrity is largely determined by the condition of particular living organisms. Coral reefs may be the best known examples of such biologically structured habitats. Not only is the substrate itself biogenic, but the diverse assemblages residing within and on the reefs depend on and interact with each other in tightly linked food webs. Based on results from multiple long-term monitoring programs within the sanctuary and separate, focused research projects, this question is rated as "fair/poor" because selected habitat loss or alteration has caused or is likely to cause severe declines in some but not all living resources or water quality. In addition, evidence suggests conditions appear to be "declining."
Coral habitats throughout the sanctuary have been in decline since the late 1970s, principally due to white-band disease and several bleaching events (Dustan and Halas 1987, Jaap 1988, Porter and Meier 1992). Prior to Caribbean-wide coral decline, many reef areas displayed a zonation pattern dominated by three scleractinian coral species: elkhorn coral, staghorn coral, and boulder corals of the genus Montastraea (Jackson 1992). Populations of elkhorn and staghorn coral underwent a region-wide decline during the 1980s and 1990s, with losses of 95% or more in some areas, principally due to white-band disease and locally due to storm damage (Figure 28; Gladfelter 1991, Bythell et al. 1993, Aronson and Precht 2001, Gardner et al. 2003). Some scientists have suggested that the loss of these species may have led to increases in algae, reduced rates of reef accretion, and erosion of the reef framework (Aronson and Precht 2001).
In 1995, the Florida Keys Coral Reef Evaluation and Monitoring Project (CREMP) was initiated to provide data on status and trends of hard-bottom and coral reef habitat in the Florida Keys. This long-term monitoring of nearshore coral habitats indicates both a decline in coral species richness and coral cover at the stations surveyed. Since the first monitoring event in 1996, mean species richness has declined sanctuary-wide, with an average loss of two species per survey station. This loss is attributed to a significant decline in the presence of 13 of the 46 species reported for the sanctuary, perhaps most importantly boulder coral (Montastraea spp.). Similarly, the percent of stony coral cover declined from 12.7% to 6.6% sanctuary-wide (Figure 29), most precipitously from 1996 to 1999 (falling from 12.7 % to 7.9%). Between 1996 and 2008, coral cover reached its lowest level in 2006 (6.4%) and has remained relatively similar since. For example coral cover was 6.6% in 2008 (Ruzicka et al. 2010). However, it is noted that these data have an inherent bias in that the study sites do not encompass all the diverse hard-bottom and coral reef habitats that vary in topographic complexity, depth, cross-shelf position, geological development and ecological history within the sanctuary.
For example, a complementary sanctuary-wide monitoring program conducted by University of North Carolina, Wilmington since 1998 corroborates some of the findings presented in the previous two paragraphs, with the following notable exceptions. Many areas, especially patch reefs and the deeper fore-reef environment, continue to exhibit relatively high cover (>25%) by reef-building corals. Low-relief, hard-bottom areas, which tend to be dominated by turf algae, sponges and gorgonians, have exhibited little change in over 10 years of surveys. Although declines in the number of corals are apparent for certain habitats, this is not a universal pattern (see Table 3 in Rutten et al. 2009), indicative of the high degree of spatial and temporal variability of hard-bottom and coral reef habitats in the Florida Keys (Miller et al. 2002, Rutten et al. 2009)
The seagrass beds that carpet most of the south Florida shelf, including the sanctuary, are part of the largest documented contiguous seagrass beds on Earth (Fourqurean et al. 2002). Seagrass habitats have been monitored as part of the Water Quality Protection Program since 1995. These extensive meadows are vital for the ecological health of the sanctuary and the marine ecosystems of all of south Florida. This seagrass monitoring program has yielded evidence showing more widespread, long-term changes in the seagrass communities at stations that are annually surveyed. These changes are consistent with model predictions of nutrient-induced changes of these systems. Although no significant overall loss of seagrass coverage in the sanctuary has occurred since monitoring began, there have been significant changes in the species composition of seagrass communities. For example, 13 of the 30 permanent monitoring stations exhibited shifts in the dominant species of seagrass, which points to increasing nutrient availability at those sites. In other words, slower-growing species (i.e., turtle grass, Thalassia testudinum) are being replaced by faster-growing species (i.e., shoal grass,Halodule wrightii) (Figure 30). Three of the 30 permanent monitoring stations were buried by sand and have remained so since Hurricane Georges in 1998. The spatial pattern of changes and the agreement of the changes with models of the system suggest that there is regional-scale change in nutrient availability that is causing changes in seagrass beds over a wide portion of the sanctuary (Fourqurean 2009).
From 1987 to 1991, a significant seagrass die-off occurred in Florida Bay (Robblee et al. 1991, Zieman et al. 1999). It is not completely understood what caused this event, however salinity, nutrient conditions, and light levels are thought to be potential causes. Following the seagrass die-off, an algae bloom occurred, followed by sponge die-off (Butler et al. 1995, Hunt and Nuttle 2007).
Injuries to seagrass caused by small boats are also a chronic problem. Monroe County has approximately 30,000 acres of significantly scarred seagrass beds, more than any other county in Florida. Most propeller scarring is due to the actions of inexperienced or careless boaters. Propeller damage not only destroys the seagrasses, but also results in a change in the hydrology of the bed from the altered movement of water through the channel within the scar. Propeller scars may take anywhere from two to 26 years to recover (censu Hammerstrom et al. 2007). If the prop scar is deep enough, it will require filling to allow rhizomes to grow across the un-vegetated gap (Kenworthy et al. 2002).
Many acres of coastal mangrove habitat have been lost from the Florida Keys due to historic and continuing shoreline development. Many canal communities were created by dredging areas dominated by mangroves and filling areas adjacent to the canal cuts to create land for development. Loss of mangrove habitat has severely reduced the ecosystem's ability to filter runoff, thus causing an increase in nutrient export to adjacent waters. A healthy mangrove community is critical to stabilizing shorelines, sustaining economically important fisheries by providing nursery habitat, providing nesting and roosting sites for birds, and maintaining the character and beauty of the Florida Keys. Mangrove resources are vast and the trusteeship for these important communities is shared between the sanctuary and the FDEP. NOAA Fisheries Service also plays an important role in protecting mangrove habitat, which serves as essential fish habitat for managed fish species. Because there have been no comprehensive time-series studies of mangrove abundance and distribution throughout the Florida Keys (but see Strong and Bancroft 1994), sanctuary staff have identified this need in the Florida Keys National Marine Sanctuary Comprehensive Science Plan (2002), specifically to assess historic shoreline conditions using aerial photography and evaluate these data and develop priority restoration plans for mangroves in the sanctuary.
Coastal habitats are often drastically altered or compromised by the effects of hurricanes and associated strong winds, storm surges, flooding, and high-energy waves. For example, increases in hydrodynamic activity can compromise the structural integrity of reef zones by fracturing or dislodging corals. Sediment is often shifted and subsequently can bury corals or seagrasses. Storm surge and winds can uproot mangroves and modify beaches. Increased runoff resulting from heavy rains and wind can result in increased pollution (e.g., raw sewage, bacteria, pesticides, fertilizers, oil and gas spills, toxic chemicals, etc.) entering the system, thus making it difficult for corals and other habitat-forming biota to regenerate. Hurricanes can also increase the rate of erosion or result in land subsidence. To date, such effects of hurricanes in the sanctuary are estimated and anecdotal because only a few biological studies have been completed (see Fong and Lirman 1994, Fong and Lirman 1995, Lirman and Fong 1997a, b).
Fishing gear and associated marine debris can have a detrimental effect on the condition of biologically structured habitats. For example, in 2010 500,000 lobster traps and 315,000 (commercial) stone crab traps licensed by the Florida Fish and Wildlife Conservation Commission (FWC) in the Florida Keys. Although routine trap placement and retrieval causes few, small injuries to sessile flora and fauna, only 34% of those injuries recover (Matthews et al. 2004). Furthermore, the FWC estimates that upwards of 20% of trap gear is "lost" annually (up to 100,000 traps), with even higher losses (>75%, such as during 2005) during active storm years. Because of their high number, long-term placement, and potential to move during storms, lost traps may have a chronic effect on sessile flora and fauna (Matthews et al. 2004).
The placement of illegal casitas (lobster attraction structures) and the subsequent lobster capture is common in the backcountry area north of the lower Keys. Casitas are usually constructed from materials such as concrete cinder blocks, tin roofing material and modified trash dumpsters. There is concern among wildlife management agencies that there could be detrimental effects to natural habitat and lobster population dynamics as a result of this type of debris. Placement of these structures on the seafloor violates sanctuary regulations and alters sanctuary habitats, and when disrupted by storms have the potential to damage marine resources.
Furthermore, in a typical year, approximately 100 boats are abandoned in the Florida Keys. In addition to this number, the 2004 and 2005 hurricane seasons caused more boats to be moved into sensitive habitats like seagrass beds and mangrove islands. After the 2005 hurricane season, Monroe County initially surveyed 355 vessels aground, but cleanup operations ultimately removed nearly 500 vessels from the water. A concerted effort to document the spatial extent, amount and impacts of marine debris in 2008 indicated derelict angling and trap gear is ubiquitous in the sanctuary, even within no-take zones. The sheer amount of debris recovered annually is testament to an increasingly visited and exploited marine ecosystem (Miller et al. 2008).
Vessel groundings in the Florida Keys occur regularly, and each impacts the benthic environment. The significance of these groundings, and associated restoration alternatives, was detailed in the Florida chapter of the "State of the Coral Reef Ecosystems of the United States and Pacific Freely Associated States: 2005" (Andrews et al. 2005). In the Florida Keys, the number of reported vessel groundings decreased annually from 2002 to 2006 (from 721 groundings in 2002 to 301 in 2006). However, it is not possible to determine if this trend is a result of fewer boaters in the sanctuary, higher fuel costs, increased boater awareness, or a decreased willingness to call for assistance if boaters run aground. Generally, there has been no proportional shift in impact to different habitat types, with approximately 14% of groundings in coral reef habitats, an estimated 85% in seagrass and about 1% on hard bottom (Donahue et al. 2008).
7. What are the contaminant concentrations in sanctuary habitats and how are they changing?
Contaminants of concern that are addressed in this question include pesticides, pharmaceutical products, hydrocarbons, and heavy metals. Toxins that are produced by harmful algal blooms and other water quality parameters are addressed in other sections of this document. To date, there have only been a few studies (e.g., Glynn et al. 1989, Singh et al. 2010) investigating the effects of contaminants on marine organisms in the Florida Keys; therefore, little synthesis of information is possible at this time to indicate a) the geographic extent and spatial variation in concentrations of various contaminants, b) the temporal variability of these concentrations, and c) contaminant pervasiveness and toxicity to organisms. As a result, this question is rated as "undetermined" and similarly the trend is rated as "undetermined."
Although a comprehensive report on contaminants in the sanctuary is not available, it is known or suspected that:
- Some nearshore waters of the Florida Keys are contaminated to an unknown extent from pharmaceuticals in sewage. Potential local sources of contamination include: solid waste and sewage disposal practices, marinas and live-aboards, seepage from municipal landfills, mosquito control programs, and surface water runoff (Rumbold and Snedaker 1999).
- The practice of soaking wooden lobster traps in used engine oil, or similar products, prior to their deployment was outlawed in 1993. At that time, approximately 670,000 traps were fished statewide, with more than 90% of traps deployed in Monroe County (FWC Fishery Statistics); a wooden trap was estimated to soak up about a quart of oil.
- It is still common practice in the sponge fishery to use vegetable oil as a way to increase "visibility" through the surface of the water while poling for sponges (S. Donahue, FKNMS, pers. obs.).
- Of the more than 300 small-vessel groundings that occur each year in the sanctuary, a few are associated with fuel and shipboard chemical spills (e.g., lubricants, solvents, and paints). Over time, these spills dissipate or break down, but their constituent chemicals may remain in the habitat for years.
- Because of the Florida Keys' proximity to a heavily used shipping lane, potential oil and other chemical spills from container ship and transport vessels remains a threat.
8. What are the levels of human activities that may influence habitat quality and how are they changing?
The level of human activity impacting sanctuary habitat quality is rated as "fair/poor," because selected activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem. The trend is rated as "declining" because of continued impacts from a diversity of activities and increasing levels of visitation to the Keys.
The Florida Keys and its environs have a long history (>100 years) of exploitation, thus many of this historically abundant megafauna (e.g., green turtles) and habitats have already been severely altered or reduced. As a result, resource managers are conserving pieces of the former system. For example, green sea turtles once served an important role in maintaining seagrass habitat quality; however, these turtles were extensively hunted for food in the Keys before the 19th century and suffered drastic population declines (Jackson et al. 2001). Jackson et al. (2001) suggested herds of turtles cropped the turtle grass very short when grazing, which helped keep organic matter from accumulating in the sediments. This accumulation now fuels microbial populations and promotes low-oxygen conditions in the sediments beneath the plants. Manatees, which were also more abundant in the past, played a similar role in keeping the seagrasses cropped. Because people have hunted and depleted these key species to endangered status, seagrasses often become so overgrown that they shade the bottom habitat and start to decompose in place, thus making the seagrass susceptible to wasting disease (Robblee et al. 1991).
As was previously described, habitat destruction resulting from human population increases over the past century has resulted in a decline of mangroves, corals and seagrass. These losses have cascading impacts on other ecosystem services. The construction of the Overseas Highway, uncontrolled upland development (including dredge and fill operations), and shoreline hardening (via seawall construction) are further examples of human activities that have damaged habitat quality through the 1970s. Although many of these activities still occur within the sanctuary boundaries, they are now highly regulated.
Despite the fact that the human population in the Keys has decreased over the short term, coastal development and land use will continue to impact habitat quality. Urban runoff from nonpoint pollution sources can diminish water quality and transport pollutants to the marine environment. Illegal discharges also have the potential to increase nutrients in surrounding waters. Illicit discharges occurring outside sanctuary boundaries (e.g., as evidenced by tar balls) can introduce toxins to the nearshore environment. Other anthropogenically driven factors such as climate change, sea level rise and ocean acidification are large-scale issues that may also affect habitat quality.
Since the 1990s, fishing pressure from the commercial sector has decreased, although recreational and commercial fishing pressure continues to affect habitat quality. For example, damage to the benthic habitat can result when mobile fishing gear, such as trawl nets or traps, are utilized. Derelict fishing gear and other marine debris can also scar or destroy benthic habitat, such as reefs or seagrasses, when entangled or dragged on the sea floor (Donohue et al. 2001, Chiappone et al. 2005). In recent surveys, marine debris in the Florida Keys including derelict fishing gear has been recorded in similar or greater amounts when compared to surveys from the past ten years (Chiappone et al. 2005, Miller et al. 2010).
Surveys of marine debris, including derelict fishing gear, entangled on the seabed in hard-bottom and coral reef habitats have been conducted intermittently by UNCW during 2000-2001, 2008, and 2010 in the Florida Keys (Chiappone et al. 2002a, 2004, 2005). Earlier (2000-2001) surveys indicated that hook-and-line gear, especially monofilament line, and remnant lobster traps, especially buoy lines, were the predominant debris items. Debris types causing the greatest degree of abrasion damage to sessile invertebrates such as sponges and corals were hook-and-line gear (68%), especially monofilament line (58%), followed by debris from lobster traps (26%), especially rope (21%). A concerted effort to document the spatial extent, amount, and impacts of marine debris in 2008 indicated derelict angling and trap gear is ubiquitous in the sanctuary, even within no-take zones. The sheer amount of debris recovered annually is testament to an increasingly visited and exploited marine ecosystem (Miller et al. 2008).
During 2008, a total of 686 pieces representing 59 different debris items or categories were recovered from 34,800 square meters (374,600 square feet) of sampled benthic habitat at 145 sites from Key Largo to Key West, with 443 kilograms (980 pounds) (wet weight) of debris removed. Of the 686 total debris items counted and retrieved, 363 (53%) items were hook-and-line gear (monofilament, wire leaders, hooks, lead sinkers, etc.), followed by 241 trap debris items (35%), and other debris (82 items, 12%). A total of 156,515 feet (477.6 meters) of angling gear was measured and retrieved from the bottom, mostly represented by monofilament line and wire leader. Over 3,000 feet (940 meters) of trap rope, either free (not attached to something), or attached to wooden slats or metal gratings, was measured and retrieved. Hook-and-line gear was the most frequent category of marine debris in terms of the number of sites and number of items encountered. Lost angling gear is ubiquitous throughout the Florida Keys, and was present at 59% of the sites sampled. Mid-channel patch reefs (1.35 ± 0.49 items per 60square meters) and high-relief spur and groove (0.66 ± 0.15) yielded the greatest angling gear densities. No-fishing zones and corresponding reference areas were roughly similar in terms of lost hook-and-line gear densities for most habitats, and in several instances, angling gear densities were greater within sanctuary no-take zones.
Lobster and crab trap debris was the second most frequent category of marine debris encountered in 2008 in terms of the number of sites present and the number of items retrieved. Trap debris consisted of rope, wooden slats, cement slabs, plastic pot openings and metal mesh trap grating, not including intact but un-buoyed traps on the seabed. The distribution of trap debris indicates that, like trap gear, it is ubiquitous throughout the Florida Keys in all of the habitats sampled (58.6% of sites). Nearshore habitats yielded greater densities than offshore habitats, and, similar to lost hook-and-line fishing debris, no-take zones and reference areas were roughly similar in terms of trap debris for several of the habitat types.
Groundings by small vessels less than 50 feet (15 meters) in length occur regularly and cause measurable impacts to habitat quality in the Florida Keys. Grounding damage from the propeller, hull, engine, or anchor usually results in significant injury to coral reefs and seagrass habitat (NOAA 2007). Although the number of reported vessel groundings has decreased annually since 2002, unreported groundings are known to occur by the damage they leave behind. Groundings often cause immediate habitat devastation with long-term impacts that require years to decades to recover (Donahue et al. 2008, Farrer 2010).
Diver impacts from recreational snorkeling or scuba diving can damage habitat in locations that receive heavy visitation. For example, inexperienced divers often damage coral as a result of excessive contact with corals due to poor buoyancy control (Talge 1989).
Lastly, the severity of the impacts from treasure salvaging (i.e., activities by those entities with legitimate admiralty judgment and rights) on sanctuary resources is somewhat unknown, but is regulated. This activity is only allowed through a Research and Recovery Permit in areas devoid of coral, hard-bottom and seagrass communities. The use of so called "mailboxes" or blowers to remove sand from a target site on the seafloor can create three- to five-meter diameter holes; however, the depressions are likely to fill back in over time as influenced by daily current, wave action and storm events. Most legitimate treasure salvage activity is presently occurring in the Hawk Channel and Quicksands area around the Marquesas in the lower Keys, with a limited amount occurring over sandy bottoms in the upper Keys.
Habitat Status and Trends
Status: Good Good/Fair Fair Fair/Poor Poor Undet.
Trends:
▲ Conditions appear to be improving.
- Conditions do not appear to be changing.
▼ Conditions appear to be declining.
? Undeterminted trend.
N/A Question not applicable.
# |
Status |
Rating |
Basis For Judgement |
Description of Findings |
5. |
Abundance/ Distribution |
|
In general, mangrove and benthic habitats are still present and their distribution is unchanged, with the exception of the mangrove community, which is about half of what it was historically. The addition of causeways has changed the distribution of nearshore benthic habitats in their vicinity. |
Selected habitat loss or alteration has taken place, precluding full development of living resource assemblages, but it is unlikely to cause substantial or persistent degradation in living resources or water quality. |
6. |
Structure |
|
Loss of shallow (<10 meters)Acropora and Montastreae corals has dramatically changed shallow habitats; regional declines in coral cover since the 1970s have led to changes in coral-algal abundance patterns in most habitats; destruction of seagrass by propeller scarring; vessel grounding impacts on benthic environment; alteration of hard-bottom habitat by illegal casitas. |
Selected habitat loss or alteration has caused or is likely to cause severe declines in some but not all living resources or water quality. |
7. |
Contaminants |
?
|
Few studies, but no synthesis of information. |
N/A
|
8. |
Human Activities |
|
Coastal development, highway construction, vessel groundings, over-fishing, shoreline hardening, marine debris (including derelict fishing gear), treasure salvaging, increasing number of private boats, and consequences of long-term changes in land cover on nearshore habitats. |
Selected activities have caused or are likely to cause severe impacts, and causes to date suggest a pervasive problem. |
Living Resources
The following information provides an assessment by sanctuary staff and experts in the field of the status and trends pertaining to the current state of the sanctuary's living resources:
9. What is the status of biodiversity and how is it changing?
Selected biodiversity loss has caused or is likely to cause severe declines in some but not all ecosystem components and reduce ecosystem integrity; therefore, this question is rated as "fair/poor." Recently the relative abundance and diversity across a spectrum of species has been substantially altered by both natural and anthropogenic pressures, particularly large reef-building corals, long-spined sea urchins, and large-bodied fish. Combine the changes in abundance with low recruitment rates of those same species and the likelihood that those species will rebound in abundance is questionable. Furthermore, numerous fisheries5 (e.g., lobster, crab, shrimp, sponges, fin-fish, aquarium trade) continue to remove individuals from the system, affecting sanctuary biodiversity and function. For these reasons, the trend is rated as "declining."
It is important to note that the "declining" trend rating could be open to interpretation because of the difficulty in applying a single trend rating that is representative of all individual trends in species abundance. For example, it is thought that species richness, as defined by the number of species found in a particular area, has changed little over the last four decades. Similarly, no species in the sanctuary are known to have become locally extinct during the same time period, although there are species which are threatened or endangered with extinction. At least three exotic species (described in Question 11) have also recently become established. Shifts in the relative abundance of multiple species, especially those at higher trophic levels, are indicators of compromised native biodiversity and stability in the system that can impact community and ecosystem structure and function. Understanding the degree of change in biodiversity that has occurred over time and how the coral reef ecosystem functioned in a "pre-exploitive" state can help managers and stakeholders identify realistic ecological and socioeconomic targets for maintaining or improving ecosystem services.
A historical perspective of sanctuary biodiversity suggests that many of the higher-trophic-level species, such as marine mammals and predatory fishes, were dramatically reduced by hunting and fishing prior to the sanctuary's designation. Current research on the historical ecology in the Florida Keys documents only one species extinction in the last 200 years - the Caribbean monk seal (Monachus tropicalis). Monk seals were historically ubiquitous and abundant in the Caribbean and the Florida Keys, but were hunted to extinction by the early 20th century (McClenachan and Cooper 2008). As such, the Caribbean monk seal was listed in the Endangered Species Act (1967-2008; 73 FR 63901). Other marine mammals found in the area of the sanctuary include cetaceans and manatees, although there is no historical record of those taxa being hunted or fished in significant numbers. However, fisheries for reef fishes and mollusk and crustacean invertebrates (conch, shrimp, stone crab, lobster) have existed in the Florida Keys in some cases for almost 300 years.
Numerous fish species in the sanctuary have been heavily exploited since the 18th century and have experienced population declines during the 20th century to unprecedented low population levels. Native Americans fished for reef fishes on Florida reefs long before the arrival of European settlers (Oppel and Meisel 1871). Reef fishing accelerated in the 1920s. Following growing public conflicts and sharp declines in catches, monitoring programs at the species level began in the early 1980s (Bohnsack et al. 1994a, Bohnsack and Ault 1996, Harper et al. 2000, Ault et al. 2005a). Ault et al. (1998) assessed the status of reef fish stocks and determined that 13 of 16 groupers, seven of 13 snappers, one wrasse (hogfish) and two of five grunts were overfished according to federal (NOAA Fisheries Service) standards (Figure 31). In addition, some stocks appeared to have been chronically overfished since the 1970s, with the largest, most desirable species depleted first, followed by increasingly smaller and less desirable species with time (Ault et al. 1998). The average size of adult black grouper in the upper Keys was about 40% of its 1940 value, and the spawning stock for this species was less than 5% of its historical, unfished maximum potential (Ault et al. 2001). In subsequent analyses, Ault et al. (2005a and 2005b) determined that 25 of the 34 species within the snapper-grouper complex for which sufficient data were available were experiencing overfishing. Closures of the fisheries at the state and federal levels for goliath (Epinephelus itajara; 1990) and Nassau (Epinephelus striatus; 1992) grouper remain in effect, although the goliath grouper stock continues to indicate signs of slow recovery (Porch et al. 2003, 2006) to the extent that considerable debate occurs regarding re-opening of that fishery. In its 2010 report to Congress, the NOAA Fisheries Service classified nine species that are landed in the Florida Keys as overfished (i.e., depleted below minimum standards), and 11 species as subject to overfishing (i.e., being fished at a rate that would lead to being overfished), with some overlap between the two categories (NMFS 2010) (Table 1).
Table 1. Southeast regional stocks that are subject to overfishing or are overfished as defined by NOAA Fisheries Service. Although the sanctuary does not manage fisheries, it straddles both the South Atlantic and Gulf of Mexico fisheries management council jurisdictions. The below list includes species in both the South Atlantic and Gulf of Mexico fishery management council jurisdictions as of 2009. (Source: NMFS 2010)
Subject to Overfishing |
Overfished |
Vermillion snapper (South Atlantic only) |
Red snapper |
Red snapper |
Snowy grouper (South Atlantic only) |
Snowy grouper (South Atlantic only) |
Black sea bass (South Atlantic only) |
Red grouper (South Atlantic only) |
Red porgy (South Atlantic only) |
Black sea bass (South Atlantic only) |
Pink shrimp (South Atlantic only) |
Gag grouper |
Red grouper (South Atlantic only) |
Speckled hind (South Atlantic only) |
Gag grouper (Gulf of Mexico only) |
Warsaw grouper (South Atlantic only) |
Gray triggerfish (Gulf of Mexico only) |
Tilefish (South Atlantic only) |
Greater amberjack (Gulf of Mexico only) |
Greater amberjack (Gulf of Mexico only) |
|
Gray triggerfish (Gulf of Mexico only) |
|
The resulting reduction in numbers of large fishes and loss of spawning aggregations affects ecosystem integrity and biodiversity. Former spawning aggregation sites are not functioning the way they did historically and quantitative anecdotes from experienced fishers point towards reduced numbers of spawning aggregations and fewer, smaller individuals within those that are still present. Researchers from NOAA Fisheries Service and Florida's Fish and Wildlife Research Institute have been monitoring one recovering spawning aggregation for mutton snapper (Lutjanus analis) at Riley's Hump in the Tortugas Ecological Reserve (South) since 2004. According to observers in 2009, "thousands" of mutton snapper (Lutjanus analis) aggregated for spawning purposes at this site (Figure 32; Burton et al. 2005).
Sea turtles have been hunted for centuries throughout the Caribbean and have lost essential nesting beaches throughout their range. McClenachan et al. (2006) showed that although some nesting sea turtle populations are beginning to recover, the long-term effect of reduced numbers of sea turtles and nesting beaches will delay the recovery of the green and hawksbill species in the Caribbean basin. American crocodiles also utilize components of the sanctuary for their survival. They were listed as endangered species in 1975 due to the loss of critical habitat from coastal development, but have been gradually recovering throughout its range. The species was recently upgraded on the federal listing to "threatened" but remains on the state of Florida's endangered list.
The smalltooth sawfish once ranged from New York to Florida to the U.S. Gulf Coast. It was listed as an endangered species in 2003. Its decline was the result of habitat degradation and loss and mortality resulting from both targeted fishing and by-catch from other fisheries (Carlson et al. 2007). The smalltooth sawfish was the first cartilaginous fish to be included on the Endangered Species List. Today, the population center is located in Florida Bay and the Ten Thousand Islands area of the Everglades National Park , but individuals are occasionally encountered in the sanctuary as far west as the Marquesas.
Biodiversity change is hard to measure for seabirds in the sanctuary. In recent times, no seabird species have been lost or extirpated from sanctuary waters. Nesting species, roosting species, wintering species and species migrating through are still being recorded in roughly the same numbers. The sanctuary has more information for coastal species such as magnificent frigatebirds, least terns (Sternula antillarum), roseate terns (Sterna dougallii), bridled terns (Onychoprion anaethetus), sooty terns (Onychoprion fuscatus), brown noddies (Anous stolidus) and masked boobies (Sula dactylatra), but little to no information on most pelagic species (those which spend most of their life at sea and do not breed in Florida) such as shearwaters and petrels.
Invertebrate biodiversity has changed during the last century. Studies of invertebrate populations have shown that:
- The long-spined sea urchin is considered an important herbivore on Caribbean coral reefs. Populations, especially in areas where overfishing has reduced populations of herbivorous fishes, suffered a mass mortality event in the Caribbean basin, including the Florida Keys, from 1983 to 1984 (Lessios et al. 1984, Lessios et al. 2001). This mortality event is recognized as "one of the most spatially expansive and prolonged disturbances to reef ecosystems in the region" (Carpenter 1988, Lessios 1988, 2005, Miller et al. 2008). The Florida Keys population suffered a second die-off event in 1991 (Forcucci 1994). Although long-term monitoring shows increased long-spined sea urchin occurrence and average size since 1999, there has been slow recovery of adult long-spined sea urchins in most habitats, with the exception of patch reefs (Miller et al. 2008, Chiappone et al. 2008).
- Sponge populations in hard-bottom areas have been periodically decimated since 1844 (Donahue 2008), most recently by two Synnechococcus sp. cyanobacterial blooms in 1995 and 2007. The historical sponge fishery also greatly reduced the density and abundance of certain sponge species. Over the entirety of the intensive sponge fishery (ca. 1850 to 1940), it is estimated that 1.5 billion pounds of sponges were removed from the northern Caribbean (McClenachan 2008). The decline of the sponge population has impacted ecosystem services, such as water filtration and ontogenetically important shelter habitat for fishes and invertebrates.
- Queen conch were commercially and recreationally fished until a moratorium was instituted by the state of Florida in 1985 due to concerns of overfishing. Results of a long-term monitoring program show adult queen conch density and abundance have increased at least three-fold from 1992 to 2006, but greater increases were negated due to the active hurricane seasons of 2004 and 2005 (Hunt 1987, Glazer and Delgado 2003). The ecosystem effects of a reduced queen conch population are not definitively known. However, researchers (Stoner et al. 1995, Torres 2003) have shown that queen conch strongly affect community structure, through their roles as herbivores and detritivores, by influencing the vegetative structure that provides forage and shelter for other benthic invertebrates. The removal of such a previously abundant invertebrate may also have an impact on species (e.g., Caribbean spiny lobster, loggerhead turtles, other marine snails) that use queen conch as prey.
- The commercial collection and sale of live reef species is a small but well-managed fishery in the Florida Keys (otherwise known as the marine aquarium or ornamental trade). State-wide landings in 2005 included 147,290 total finfish and 8,611,912 individual invertebrates (e.g., polychaete worms, tunicates, crabs, sea stars and anemones). The fishery has been regulated by the state fisheries agency (currently the FWC) since 1991. Although Florida Keys fishermen have been exemplary in initiating regulations for their fishery, and noting fluctuations in the variety of species they fish, there are currently no independent stock assessments for the species they target. Approximately 147 endorsements (permits) were issued for the live collection of ornamental vertebrates and invertebrates for sale in the aquarium industry in Monroe County in 2007.
Lastly, it should be noted that the status and changes to the biodiversity of habitat-forming organisms (e.g., coral, seagrass) were described in the "Habitat" section of this report.
10. What is the status of environmentally sustainable fishing and how is it changing?
The status and trend ratings for this question are based on the available scientific knowledge from published studies, unpublished data, and expert opinion for targeted and non-targeted living resources that are directly and indirectly affected by fishing. Because this is the sanctuary's first condition report, the rating combines the historical view of the potential effects of fishing activity on biological community development, and ecosystem function and integrity, with the targeted research of species-specific fisheries over the last three to four decades. The rating reflects conditions in the sanctuary but does not serve as an assessment of the status of current fisheries management practices in the region. However, the determination of the trend rating for this question reflects recent changes in fisheries management practices that may have potential beneficial effects on living resources in the sanctuary. The response to this question is a rating of "fair/poor" because fisheries extraction has caused or is likely to cause severe declines in some but not all ecosystem components and reduce ecosystem integrity. The trend is rated as "undetermined" because predictions are difficult to make regarding potential ecological gains resulting from newer fishing regulations and sanctuary zones that prohibit extraction. Benefits of recent management changes could be offset by illegal fishing practices, changing patterns and amounts of recreational fishing effort, chronic marine debris in the form of trap fishery losses and illegal casitas placement, and invasive marine species (e.g., Indo-Pacific red lionfishesPterois volitans and P. miles and orange cup coral Tubastrea coccinea). Less than 6% of the sanctuary's waters are considered "no-take."
Environmentally sustainable fishing or ecologically sustainable fishing may be defined as fishing at a level that the ecosystem can sustain without shifting to an alternative or undesirable state. To determine if environmental sustainable fishing is occurring, one has to simultaneously consider the impacts of all exploited species on an ecosystem, including its stability and resilience (Zabel et al. 2003). In addition, fishery yield and the integrity of ecosystem structure, productivity, function, and biodiversity (including habitat and associated biological communities) must also be considered. The past decade has seen a paradigm shift in the management focus of fisheries from managing individual target stocks for maximum sustainable yield to ecosystem-based fisheries management. This shift leads to a more holistic consideration of sustaining fishery yield, as well as maintenance of marine ecosystems and their function. Some fishery data were described in other questions of this document (see Questions 6 and 9) and that information should be considered along with the additional detail provided here. Generally, fishing can reduce ecosystem integrity in three ways: first, removing targeted species and killing non-target species (as bycatch) may result in cascading ecological effects (Frank et al. 2005). Second, because fishing is size-selective, concerns exist about ecosystem disruption by removal of ecologically important species such as top-level predators (e.g., groupers, snappers, sharks, jacks) and prey (e.g., shrimps, baitfish) of certain sizes. Third, fishing can stress all habitat types in the sanctuary in the form of physical impacts of fishing gear to the habitat and by introducing marine debris. For example, regular yet unintended trap loss in the lobster and stone crab trap fisheries results in trap ropes wrapping around coral heads and abrading or killing coral colonies. Combined, the two fisheries utilize approximately 815,000 traps per season in addition to an unknown number of recreational stone crab traps (five per person allowable with a Florida saltwater fishing license) have the same potential for habitat impact. In addition, lobster or stone crab traps can continue "fishing" even after they have been lost, which leads to continued mortality of marine organisms that are too large to escape the traps after capture6.
For the 1996 to 2006 period, Murray (2007) summarized various measures of fishing effort for Monroe County relative to "other Florida counties"(Table 2). Over this period, all measures of fishing effort declined more rapidly in Monroe County relative to all other counties in Florida, except for stone crab permits.
Table 2. Changes in commercial fishing effort in Monroe County between 1996 & 2006. (Source: in Murray 2007, data from FWC)
Effort Measure/Area |
1996 |
2006 |
Change between 1996 and 2006 |
Saltwater Produc Licenses |
2,895 |
1,636 |
-43.49% |
Commercial Boats |
4,194 |
2,921 |
-30.35% |
Commercial Fishing Trips |
67,773 |
35,811 |
-47.16% |
Stone Crab Permits |
1,198 |
459 |
-61.69% |
Lobster Permits |
1,270 |
704 |
-44.57% |
Lobster Fishing Trips |
29,039 |
14,278 |
-50.83% |
Generally, there is a very high exploitation rate in the Keys from both recreational effort and commercial effort. Trends in reef fish landings from 1981 to 1992 were reported for the Florida Keys by Bohnsack et al. (1994a). Depending on the year, recreational landings comprised between 40% and 66% of total landings. Reef fishes accounted for 58% of total fish landings, 69% of recreational landings, and 16% of commercial landings. Commercial landings were dominated by invertebrates (Caribbean spiny lobster, shrimp, and stone crabs), which comprised 63% of total landings. But trends in recreational and commercial fishing pressure in Monroe County/Florida Keys are in decline due to a number of fishery and extra-fishery factors, including stagnant ex-vessel values (the revenue the fisherman receives for his catch) resulting from low demand, higher landside prices such as cost of living, gear, crew, etc., and less waterfront space availability (Leeworthy and Wiley 1996, Leeworthy 1996, Leeworthy et al. 2010, Leeworthy and Morris 2010, Murray 2007, Sharp et al. 2005). Commercial fishing catch declined from 21.8 million pounds in 1995-1996 to 9.6 million pounds in 2008, a 56% decrease. Fishing trips also declined 56% over this period, from 67,422 trips in 1995-1996 to 29,681 trips in 2008. This was a greater decline than what occurred across the entire state of Florida. Florida's total catch declined about 34% during the same period, while trips declined about 47%. The decline was due in part to changes in fishery management designed to reduce overall fishing effort, as well as decreasing demand for Caribbean spiny lobsters, which is the dominant fishery in the Florida Keys. The Florida Keys historically account for 89% of commercial Caribbean spiny lobster catch. (FWRI 2010)
Ault et al. (1998) assessed the status of multiple reef fish stocks in the Florida Keys and determined that 13 of 16 groupers, seven of 13 snappers, one wrasse (hogfish) and two of five grunts were overfished, according to federal (NOAA Fisheries Service) standards (see Figure 31). They suggested that some stocks appeared to have been chronically overfished since the 1970s, and that the Florida Keys fishery exhibits classic "serial overfishing" in which the largest, most desirable species are depleted by fishing (Ault et al. 1998), followed by sequentially smaller species. Ault et al. (2001) found that the average size of adult black grouper (Mycteroperca bonaci) in the upper Keys was about 40% of its 1940 value, and that the spawning stock for this species is now less than 5% of its historical, unfished maximum. In subsequent analyses, Ault et al. (2005a, 2005b) determined that, of 34 species within the snapper-grouper complex for which sufficient data were available, 25 were experiencing overfishing. Another game fish that has declined in numbers is the bonefish (Albula vulpes), which is at approximately 5% of historic levels primarily because of habitat and food loss (Ault 2008). Although additional, long-term monitoring is necessary to adequately understand the impacts of new fishery regulations, initial research has shown that certain fish species (e.g., black and red groupers, Epinephelus morio, and mutton snapper) have responded positively to the combination of stronger regulations and larger ecological reserves within the sanctuary. These results will be further detailed in the "Response" section of this document.
The commercial and recreational lobster fisheries are regulated by the FWC. Due to the Spiny Lobster Trap Certificate Program (370.142)7 the total number of commercial lobster traps allowed in the fishery has declined from about 750,000 in 1993 and 1994 to about 480,000 in 2010 (FWC Fishery Statistics). The Florida lobster trap fishery is unique in that it allows the use of sub-legal lobsters as a "live attractant." The consequences of this practice are well-documented in literature and include increased stress and mortality from confinement to traps (SEDAR 8 2005) and potential spread of a lethal lobster virus (Behringer et al. 2008). Fishery managers suspect that more protection for sub-legal-sized lobsters should improve landings in Florida's lobster fishery (Matthews 2001), and improve the fishery sustainability.
The queen conch is a large, marine gastropod that inhabits the tropical western Atlantic including the Florida Keys. It once supported significant commercial and recreational fisheries in south Florida; however, the ease of capture and the desirability of the shell and meat resulted in a severe depletion of the local population to the point that a ban was instituted in 1985 in state waters and then in 1986 in federal waters. When the ban was established, less than 6,000 adult conch remained in the Florida Keys (Glazer and Delgado 2003). Since then, ongoing surveys have shown a slow and very limited recovery with an estimated 33,500 adults in 2010 (FWC unpublished data).
In addition to the traditional "hook and line" and trap fishing pressure, biodiversity in the sanctuary is also affected by the aquarium trade. The collection and sale of living corals and hard substrate with attached organisms ("live rock") has been prohibited in state waters of Florida since 1995 and in federal waters since 1997. The state and federal government both regulate a small but viable fishery based in live rock aquaculture, where geologically unique limestone is placed on sandy, barren ocean floor areas and acts as a recruitment site for hard and soft corals and other marine invertebrates. This fishery remains commercial in nature because the mature live rock is sold in the aquarium trade.
Similar to live rock aquaculture, the collection and sale of live reef species comprises a small but well-managed fishery, most notably in the Florida Keys. This fishery has been regulated by the FWC since 1991, and there is currently a moratorium on the issuance of new marine life endorsements (permits). Approximately 80 commercial endorsements were renewed for the live collection of ornamental vertebrates and invertebrates for sale in the aquarium industry in Monroe County during each year from 2006 to 2009. Combined commercial landings in the Keys during the same time period included 291,672 total finfish and 14,584,831 individual invertebrates (e.g., polychaete worms, tunicates, crabs, sea stars and anemones) (source: FWC). Florida Keys commercial fishermen have initiated regulations for their fishery, recognizing fluctuations in the variety of species they fish. Concerned fishermen of the Keys continue to work with the FWC to suggest rule changes to ensure sustainability of the marine life fishery. However, there is also a recreationally allowable "catch" of marine life, and there is no way to account for the level of effort or extraction this sector represents at the current time. Lastly, but most importantly, there have been no stock assessments of any of the species collected, thus it is impossible to determine whether this fishery is environmentally sustainable over the long term.
In a recent study by Rhyne et al. (2009), the Florida Marine Life Fishery landing data from 1994 to 2007 was analyzed for all invertebrate species, and it was discovered that of the 9 million individuals collected in 2007, 6 million were grazers. The results suggest the number of grazers greatly exceeds the number of specimens collected for ornamental purposes, representing a significant categorical shift, positioning the invertebrate ornamental fishery for a collapse. More targeted research would help managers determine what effect both sectors of the marine life fishery are having on ecosystem biodiversity and integrity to help more effectively manage these resources.
Although seabirds are an integral component of the food web, more studies are needed to better assess fishing impacts on prey availability in coastal and seabird populations. Many bird species forage in or around the marine environment where they can become entangled in fishing gear, hooks and line to the extent that they are unable to feed or move about freely. Bird rescue organizations regularly treat cormorants, pelicans, herons and gulls that have become entangled or injured by fishing gear.
Shrimp are important in the diet of a wide range of species including many fish and bird species; however, they are also exploited by both recreational and commercial fisheries. Recreational "shrimping" usually occurs during the wintertime, but the effort and harvest levels associated with this sector are not known. Commercially, shrimp are harvested for both food (the pink shrimp Farfantepenaeus duorarum) and as bait for the recreational fisheries. For example, commercial landings of pink shrimp in the Florida Keys averaged 1,165,120 lbs in the years 2006-2010 (FWC statistics). Though landings have fluctuated over the last five years, it is generally not known how shrimp fishing impacts ecological sustainability.
11. What is the status of non-indigenous species and how is it changing?
Although the threats of introduced aquatic species to habitats they colonize is often unknown beforehand, some can have serious detrimental impacts, including competition with native species for food and space, alteration of habitat, predation on native species, and introduction of diseases to which native species have no resistance (Ruiz-Carus 2006). Non-indigenous species in the sanctuary are occurring with increasing frequency and may inhibit full community development and function and may cause measurable but not severe degradation of ecosystem integrity; therefore, this question is rated "fair" and "declining." More than 30 species of non-native marine fishes have been documented in Florida waters (Schofield et al. 2009), with more than 18 species of non-native marine fish being documented in Miami/Dade, Broward and Palm Beach counties in southeast Florida (REEF database 2006). Aquarium "dumping" has been identified as the likely source of these introductions given that most of the species are popular ornamental fish.
The sanctuary has been witness to the non-indigenous Pacific orbicular batfish (Platax orbicularis), which was controlled, and the Indo-Pacific red lionfishes, which are presently the only non-native marine fish species known to be established along the coast of Florida (Schofield et al. 2009) (Figure 33). Red lionfish, formerly residents of the western Pacific, Red Sea, and eastern Indian Oceans only, were first reported in the 1980s along south Florida and are now well established along the Southeast U.S. and the Caribbean (Ruiz-Carus 2006, Morris et al. 2009). Reports of lionfish in the sanctuary began in January 2009, and between January 2009 and July 2010 there were approximately 500 reported lionfish sightings in the Florida Keys (250 of those were confirmed and removed from sanctuary waters) (Morris and Whitfield 2009). Since then, sighting and removal efforts have been continuously increasing. Juvenile lionfish (approximately 30 millimeters in length) were observed in spring 2010 at several locations in Florida Bay (C. McHan, FWC, pers obs. and M. Butler, Old Dominion University, pers. comm.), suggesting a pervasive invasion is occurring across all the habitats of the Florida Keys ecosystem. The increasing abundance and wider distribution of lionfish in the South Atlantic Bight, Bermuda, Florida, and the Bahamas indicates that lionfish are the first marine fish species to successfully establish a breeding population in the tropical waters.
The venomous protective spines of lionfish, combined with their feeding habits, unique reproduction and few predators, contribute to their successful invasive abilities. Lionfish are ambush predators, can threaten local ecosystems by altering the structure of native reef fish communities by out-competing native reef organisms and reducing forage fish biomass (Morris and Whitfield 2009). Impacts from lionfish could include direct competition with groupers for food and predation on reef fish and crustaceans (Ruiz-Carus 2006, Albins and Hixon 2008, Morris and Akins 2009). Also, lionfish pose a danger to divers and fishermen - stings from the venomous spines of the fish may result in pain, swelling, numbness and sometimes more severe effects including paralysis and systemic effects.
One coral species is invasive and could potentially impact ecological integrity. The range of the non-indigenous orange cup coral (Tubastraea coccinea) (Figure 34), has expanded since it was first observed offshore of Key Largo in 1999 and now includes the Gulf of Mexico, South Florida, and the Florida Keys, including the sanctuary (Fenner and Banks 2004, Ferry 2009, Shearer 2010).
Observations in the Caribbean and the Gulf of Mexico show that this species inhabits natural reef substrates and can cause tissue necrosis and partial mortality of native corals (Creed 2006). However, in general, orange cup coral appears primarily on artificial substrates such as submerged steel wrecks (Fenner and Banks 2004, Ferry 2009, Shearer 2010). It is suspected that these artificial structures played a major role in the spread of this species. A study by Ferry (2009) indicates that orange cup coral has not yet become established in the lower Florida Keys. However, the potential for this species to impact reef communities is high due to high proliferation rates resulting from the production of asexual larvae, the ability to out-compete native species and limit substrate available for recruitment of native species, plus the lack of a natural predator.
The Red-tipped Sea Goddess, (Glosssodoris sedna), a nudibranch native to the tropical Pacific (Figure 35), has become well-established in the Florida Keys (K. Nedimyer, Coral Restoration Foundation, pers. comm.). Over the last three to four years it has become seasonally abundant in a variety of habitats. Although they have become well established, it is unknown if they pose a threat to any resources in the sanctuary.
12. What is the status of key species and how is it changing?
The key species or taxa in the sanctuary selected for use in this report include stony corals, seagrasses, queen conch, Caribbean spiny lobster, long-spined sea urchin, the snapper-grouper complex and sea turtles. These species are important for their ecological roles, and long-term datasets are available for assessing changes for these species. With the exception of seagrasses, historical data for each of these groups show substantial declines in abundance. Therefore, the status of key species in the sanctuary is rated as "poor" because the reduced abundance of selected keystone species has caused, or is likely to cause, severe declines in ecosystem integrity; or selected key species are at severely reduced levels and recovery is unlikely. The trend is rated as "not changing" because of the reduced abundance of a limited number of key species in each habitat type. Although there are very encouraging results of increased sizes and density of select species within certain sanctuary marine zones, forecasting how these changes will affect their long-term status is challenging.
Stony Corals
As discussed in earlier questions, long-term monitoring of nearshore coral habitats indicates a decline in both species richness and coral cover at the stations surveyed, and no significant recruitment has occurred since the monitoring program began in 1996 (Ruzicka et al. 2010). The declines in abundance of two of the principal Caribbean reef-building corals, staghorn and elkhorn coral, are often-cited as examples of the changes in western Atlantic reefs that have occurred over the past several decades (Aronson and Precht 2001, Gardner et al. 2003). The causes of these declines, which began in the late 1970s, include large-scale factors such as coral bleaching and disease, especially white-band disease, as well as smaller-scale effects resulting from storms and predation by corallivorous snails and damselfishes. Both staghorn and elkhorn corals were under consideration for addition to the U.S. Endangered Species List since the early 1990s and were formally added as threatened in 2006 based on Caribbean-wide population declines and poor recovery (Williams et al. 2008). The more recent declines of the massive star corals (Montastraea spp.) have also led to the overall loss of coral cover both in the Florida Keys (Ruzicka 2010) and in other parts of the Caribbean (Hughes and Tanner 2000, Edmunds and Elahi 2007). As of July 2010, the NOAA Fisheries Service was conducting a status review of 82 additional coral species for ESA consideration, seven of which occur in the Caribbean and in the sanctuary (Agaricia lamarcki, Dendrogyra cylindrus, Dichocoenia stokesii, Montastraea annularis, Montastraea faveolata, Montastraea franksi, Mycetophyllia ferox).
Seagrass
Long-term monitoring of seagrass has shown changes in coverage and nutrient composition at some monitoring stations. These changes are consistent with model predictions of nutrient-induced changes of these systems. Although no significant overall loss of seagrass coverage in the sanctuary has occurred since monitoring began, there have been significant changes in the composition of the seagrass species found in benthic communities (Fourqurean 2009). Furthermore, shallow seagrass beds are regularly subject to injury by vessel groundings.
Queen Conch
Although queen conch densities are relatively high within the sanctuary, the modest spatial extent of the aggregations results in low estimates of overall abundance. Queen conch populations are showing signs of gradual recovery from their low abundance estimates in the 1980s. Scientists from the Fish and Wildlife Research Institute are currently investigating the cause of chronic reproductive failure of nearshore aggregations. Although queen conch have been protected from fishing since 1985, in both federal and state of Florida waters, poaching still occurs on a regular basis (G. Delgado, FWC, pers. comm.).
Caribbean Spiny Lobster
Caribbean spiny lobster in the Florida Keys experience intense fishing pressure within Florida Keys National Marine Sanctuary, both from a heavily capitalized commercial fishery and a recreational fishery that is the most intensive such fishery on the globe (Sharp et al. 2005). In addition to the direct removal of lobsters by the fishery, each fishing sector also directly affects the survival rates of Caribbean spiny lobster before they recruit to the fishery. The commercial lobster trap fishery's practice of confining sub-legal-sized lobsters within traps to serve as attractants results in an estimated 10% mortality rate among these lobsters (SEDAR 8 2005). The recreational fishery results in the catch-and-release of a large number of lobsters below the legal size limit, causing injuries that result in increased mortality (Parsons and Eggleston 2007).
Although the no-take zones within the sanctuary were not designed as a fishery management tool, results from an FWC five-year monitoring project concluded that Sanctuary Preservation Areas (SPAs) were too small to protect Caribbean spiny lobsters from the fishery, but the larger Western Sambo Ecological Reserve (WSER) did function to some degree as a fishery reserve (Cox and Hunt 2005). There, the mean size of legal-sized lobsters and the frequency of occurrence of lobsters were significantly larger than those commonly encountered within the fished areas of the sanctuary, having increased steadily after WSER establishment. Cox and Hunt (2005) also concluded the increased frequency of encountering atypically large lobsters in the areas adjacent to the WSER (including the nearby fishery-exploited areas) suggested lobsters were likely emigrating from the WSER, thus this zone may serve to some degree to enhance fishery landings. The WSER does not encompass all of the habitats utilized by adult Caribbean spiny lobsters during their life history, and inclusion of the adjacent outlier reef would serve to protect lobsters from fishery exploitation (Cox and Hunt 2005).
Long-spined sea urchins
The long-spined sea urchin Diadema antillarum was considered a most important herbivore (grazer) because it helped to control the amount of algae on Western Atlantic coral reefs (Lessios et al. 2001). The demise of this once-ubiquitous echinoid is considered one of several factors responsible for the changes observed on Florida Keys reefs. Historical surveys of D. antillarum prior to the 1983 and 1984 Caribbean-wide mass mortality event are limited for the Florida Keys and consist of data collected at a few seagrass and fore-reef sites, mostly from Indian Key to reefs offshore of Key Largo. However, the available data indicate that densities were at least as high as four or five individuals per 10 square feet (one square meter) (Chiappone et al. 2008). The Caribbean-wide mass mortality began in the Florida Keys during the summer of 1983 and presumably led to a 90% or greater reduction in population size. From 1983 to 1990, there were no published studies ofD. antillarum density and size structure. Surveys carried out in the early 1990s suggested that the population was recovering, with densities on shallow spur and groove reefs approaching one-tenth (i.e., 0.5-0.6 individuals per 10 square feet) of their pre-1983 level, and a size distribution dominated by larger (>2 inches, or 5 centimeters) TD) individuals (Forcucci 1994). In contrast to other wider Caribbean reef ecosystems, a second mortality event struck the Florida Keys D. antillarumpopulation beginning in April 1991, with similar morbidity symptoms as the 1983 event that reduced the population to one-hundredth of its pre-1983 level (Forcucci 1994). Surveys conducted within one year of the 1991 mortality indicate that very low densities (<0.1 per 10 square feet) and small test sizes (<1 inch, or 3 centimeters) in shallow fore-reef habitats characterized the D. antillarumpopulation (Forcucci 1994), a pattern that continued for the next decade (Chiappone et al. 2002 b, c).
Although monitoring conducted over the past decade has detected increases in both the density and size structure of long-spined sea urchins on patch reefs, a similar trend has not been detected on offshore reef habitats. Overall, there has been slow recovery of long-spined sea urchins compared to pre die-off densities (Miller et al. 2008). Over an 11-year period (1999-2010), researchers examined densities and test sizes of D. antillarum and other sea urchins at more than 1,100 Florida Keys sites spanning 217 miles (350 kilometers), encompassing multiple habitat types from inshore to the deeper fore-reef slope. Surveys since 1999 indicate that current densities are still well below one individual per square meter and the maximum site-level density recorded during the 11-year period was only 0.33 individuals per 10 square feet (one square meter) (Figure 36). However, there has been a notable positive shift in their average and maximum size (Chiappone et al. 2008). Population recovery to pre-1983 levels could take decades, if not longer. Algal assemblages, in most habitats, despite reduced D. antillarum, are dominated by diminutive algal turfs, crustose coralline, and to a lesser extent macroalgae, suggesting that herbivorous fish grazing is critical for maintaining low algal standing crop on Florida Keys reef. Moreover, observations of newly recruited juvenile long-spined sea urchins have been largely confined to reef-rubble zones. However, because of the highly dynamic nature of the substrate resulting from wave and storm surge in this habitat, the mortality rate of these recruits is potentially substantial.
Groupers and other fishes
Previous sections of this report review the status of select species of finfish (see Questions 9 and 10). Even though sanctuary zones were not established to protect individual species, there have been encouraging observations of increased abundance and sizes of select finfish inside Tortugas Ecological Reserve (a no-take zone). Groupers in the Florida Keys have been historically exploited, and in a study by Ault et al. (1998) it was determined that 13 of 16 grouper species were overfished according to NOAA Fisheries Service standards. As of 2010, the status of grouper species has improved and according to the NOAA Fisheries Service, only three species of grouper (snowy, red, and gag) are still considered to be overfished in the same area (NOAA Fisheries Service fourth quarter 2010 "overfished map").
Specifically, the goliath grouper was targeted by commercial and recreational fishing since the late 1800s. They are extremely susceptible to exploitation due to a mixture of life history traits such as slow growth, long life, delayed sexual maturity, and the pattern of spawning aggregations. These characteristics, in association with escalating fishing pressure, led to the fishery closure in 1990 and the subsequent listing of goliath grouper as a candidate for the Species of Concern List under the U.S. Endangered Species Act. Fishery closures and designating some sanctuary zones as no-take have helped to increase the goliath grouper population as well as expand its geographic distribution. However, it is not clear as to when the population may be fully recovered, or when the fishery will be reopened if it were to be (Collins 2009, Porch et al. 2003, 2006). It is hoped that more examples of positive finfish responses to sanctuary zones continue, but the damaging ecological effects of the invasive red lionfishes could counteract management efforts.
Another study on the social structure of hogfish (e.g., harems) showed a difference between Western Sambo Ecological Reserve and the adjacent "fished" areas; spawning was only observed inside Western Sambo Ecological Reserve during a recent study (Muñoz et al. 2010).
Sea turtles
Sea turtle species frequenting the Florida Keys that are listed as endangered under the U.S. Endangered Species Act include the green, leatherback, hawksbill, and Kemp's Ridley turtles. Green sea turtles were hunted for their meat to the brink of extinction during the late 1800s and early 1900s in south Florida, and their numbers in the Florida Keys continue to remain low today. Systematic monitoring of green turtle nests on islands of the Key West National Wildlife Refuge show nearly a doubling since 1990; however, the number of nests still remains low (USFWS unpubl. data). These low population numbers affect seagrass beds, as these reptilian herbivores serve an important role in maintaining seagrass habitat quality by keeping the organic matter from accumulating in the sediments through continuous grazing. Green sea turtles are also affected by fibropapillomatosis (FP), a disease that forms large tumors on soft and hard tissues of turtles (Herbst 1994,Ene et al. 2005). In the Indian River Lagoon, Florida Bay, and the Florida Keys, 50-70% of the green turtles are affected (Ene et al. 2005) and since the early 1980s, the percentage of green turtles stranded in Florida with FP has been increasing each year (Foley et al. 2005).
Loggerhead turtles, listed as threatened, also frequent the Florida Keys. However, an updated analysis of Florida's long-term loggerhead sea turtle nesting data reveals that loggerhead nest counts have declined 25% over the last 10 years (Witherington et al. 2009). Systematic monitoring of loggerhead turtle nests on islands of the Key West National Wildlife Refuge indicates a more than 50% decline since 1990. This marked decline in the number of breeders and nests, low productivity, a high proportion of false crawls, tidal flooding coupled with ongoing beach erosion, and sea level rise collectively threaten the future of the nesting loggerhead turtle population in the sanctuary (USFWS unpubl. data). In 2010, NOAA Fisheries Service and the U.S. Fish and Wildlife Service proposed to list nine Distinct Population Segments (DPS) of loggerhead sea turtles under the U.S. Endangered Species Act. Under this proposal, the South Atlantic Ocean DPS is being considered to go from "Threatened" status to "Endangered".
In January 2010, the Florida Keys experienced record low temperatures, causing many sea turtles to become stunned by cold-water temperatures. More than 250 cold stunned turtles were recorded in January 2010, the majority of which were green turtles, with smaller numbers of loggerheads and Kemp's Ridleys. NOAA and the FWC helped to coordinate the rescue of hundreds of sea turtles to help them recover from the cold shock. Rescued turtles from the Florida Keys were housed and rehabilitated at the Sea Turtle Hospital in Marathon. The hospital is a non-profit facility that has been in operation since 1986.
Seabirds
The populations of most of the state and federally listed seabird species seem to be stable. The least tern and roseate tern nesting populations are stable but low in numbers. The roseate tern population dropped drastically after the 2005 hurricanes but has since rebounded. This was notably due to the disappearance of Pelican Shoal in the lower Keys. That site was a coral-rubble and sand island where roseate and bridled terns were nesting and the island is now underwater. The birds have shifted to nesting on roofs of large buildings in the Keys. There are no similar ground nesting sites (islands) throughout sanctuary boundaries (R. Zambrano, FWC, pers. comm.).
Manatees
The West Indian manatee includes two distinct subspecies, the Florida manatee (Trichechus manatus latirostris) and the Antillean manatee (Trichechus manatus manatus). The Florida manatee's range is confined to the southeastern U.S., while Antillean manatees are found throughout the Caribbean. Due to a variety of human activities, like coastal development, this important herbivore has declined in numbers and their distribution is patchy throughout Florida.
A U.S. Fish and Wildlife Service survey estimated there were at least 3,800 Florida manatees in 2009. Even though this population number is low compared to historic records, the population is stable due to effective management of human-related threats (e.g., establishing watercraft speed limits to prevent propeller strikes). However, the Florida manatee population was negatively affected by the prolonged cold event in January 2010, when 244 deaths (13 of which were newborns) were recorded statewide (FWC statistics).
13. What is the condition or health of key species and how is it changing?
The condition and health of key species in the sanctuary is rated as "fair/poor" because the comparatively poor condition of selected key resources makes prospects for their recovery uncertain. For example, the effect of diseases on hard and soft corals has caused substantial declines in coral cover (biomass) over the last two decades, yet there has been no significant coral recruitment recorded at any long-term monitoring station. Likewise, long-spined sea urchins have yet to recover from a 1980s Caribbean-wide disease outbreak. Generally, the health of selected key species has been compromised by factors including exposure to algal blooms (including harmful algal blooms), fishing, entanglement in active and lost fishing gear, ingestion of marine debris, and disease. Due to persistence, and accumulating effects of these problems, the trend is considered to be "declining."
Large, persistent phytoplankton blooms resulting in part from eutrophic conditions have been associated with fish kills and sponge and seagrass die-offs (Butler et al. 1995, Fourqurean and Robblee 1999, Hunt and Nuttle 2007). Cyanobacterial blooms have been especially prevalent in central Florida Bay during the past two decades and at times have been carried by the tidal currents to the ocean side of the Keys. Blooms are not necessarily triggered or sustained by a single change in nutrient load; rather, a combination of multiple biotic and abiotic factors contribute to their intensity and duration. Unfortunately, there is currently insufficient data to predict cyanobacterial bloom initiation or longevity, thus there is a need to integrate existing biological, climatological, and oceanographic research efforts so that predictive models can be further developed and refined.
A health concern for key species in the sanctuary, including marine mammals, seabirds, sea turtles and corals, is interaction with active and lost fishing gear. Results from a recent study on marine debris prevalence in the sanctuary showed "marine debris, most of which is derelict angling and trap gear, is ubiquitous in the sanctuary, even within no-take zones. The sheer amount of debris recovered is testament to an increasingly visited and exploited marine ecosystem" (Miller et al. 2008). Marine debris poses entanglement threats not only to highly migratory species (e.g., sea turtles and manatees) but also to sessile species (e.g., coral and sponges). Lost fishing gear can wrap around coral heads and cause injury, mainly from abrasion caused by wave action. Likewise, sponges can be literally cut in half by the combination of derelict gear and wave energy. In addition, ingestion of plastic marine debris is a health concern for a number of sea turtle and seabird species in the sanctuary. Although there are no quantitative studies on the frequency and severity of this occurring, it is well known that sea turtles will ingest plastic bags and balloons, mistaking the debris as prey items.
Corals throughout the Caribbean and Atlantic region have suffered from numerous diseases over the past several decades, and disease has been implicated in the demise of a number of reef-building species. Studies in the Florida Keys track disease prevalence at monitoring stations throughout the archipelago. For example, the Fish and Wildlife Research Institute's Coral Reef Evaluation and Monitoring Project has shown the prevalence of diseases to vacillate over time, and from 2002 to 2006 generally decreased at monitored stations within the sanctuary and at the Dry Tortugas. The number of stations affected with white diseases peaked to more than 80% in 2002, subsided to 35% in 2005, then increased again to 50% in 2006. The number of stations affected with "other" diseases peaked to 90% in 2001, but declined to 57% by 2006 (Ruzicka et al. 2009). A second study, which was conducted in August 2006, focused on diseases affecting two species of coral (elkhorn and staghorn coral) that had been recently listed as threatened on the U.S. Endangered Species List. One hundred and seven sites along approximately 29 miles (46 kilometers) of coastline in the upper Keys were surveyed, and no evidence of white-band or any other diseases affecting either species was observed (Miller et al. 2008). Though they are the best datasets available to resource managers, it should be noted that these types of annual surveys do not necessarily capture the real trends of disease impacts (or trends thereof) to coral populations because of the acute nature of the disease outbreaks.
Other diseases8 impacting key species include fibropapillomatosis and PaV1. Fibropapillomatosis (FP) most commonly affects juvenile green turtles in nearshore habitats. It is estimated that 50% to 70% of the green turtles in the Indian River Lagoon, Florida Bay, and the Florida Keys are affected and since the early 1980s, the percentage of green turtles stranded in Florida with FP has been increasing 1.2% each year (Ene et al. 2005, Foley et al. 2005). Another key species impacted by disease is Caribbean spiny lobster, which is susceptible to the Panulirus argusvirus 1 (PaV1 (Behringer et al. 2006).
Studies on queen conch have shown nearshore populations are no longer reproductive. Nearshore water quality is suspected to be the cause of nearshore individuals experiencing rapid loss of gonadal tissue (Delgado et al. 2004, Spade et al. 2010).
The condition or health of seabirds is unknown, although their populations seem to be stable. However, as previously mentioned, birds are as susceptible to contaminants (e.g., oil, plastic, heavy metals), as are fish and corals. Impacts to small fish will obviously reduce food for terns and thereby reduce nesting productivity (R. Zambrano, FWC, pers. comm.).
During January and February 2010, the Florida Keys and the rest of Florida experienced severe, extended cold periods that caused drastic drops in seawater temperatures, especially in nearshore waters of Florida and Biscayne Bays. Such bouts of extreme cold are uncommon, but have occurred in the recent past (1977). The cold fronts during this time period moved in rather quickly, causing fish kills in nearshore waters and cold-water bleaching of corals that resulted in nearly 100% mortality of the colonies at the locations surveyed. Results from remote sensing data (NOAA and USF) and in-water surveys (managed by the Nature Conservancy) indicated that the coldest water was in the bays and flowed to the ocean side. Mid-channel reefs in Hawk Channel were particularly affected by cold-water stress and underwent extensive bleaching. Studies have shown that these same reefs are known to be more resilient to summertime warm-water bleaching events than many other coral communities within the sanctuary (see Response section, under climate change). Many sea turtles, manatees, and American crocodiles were also affected and suffered mortality. The long-term impacts of the loss of these animals, along with the numerous fish and coral losses, are unknown at this time and somewhat difficult to predict.
14. What are the levels of human activities that may influence living resource quality and how are they changing?
Human activities affect the quality of living resources in the sanctuary directly and indirectly. Direct impacts to living resource quality include commercial and recreational fishing, vessel grounding, anchoring, propeller scarring, disposal of marine debris, and disturbance from recreational diving, snorkeling, or boating. Indirect activities result in nonpoint source pollution and illegal discharges.
Many activities, such as those related to vessel groundings, caused or are likely to cause severe impacts to sanctuary resources, and cases to date suggest a pervasive problem. Therefore, the response to this question is rated as "fair/poor." However, the trend is rated as "not changing" because all water-based human activities, whether engaged in by residents or by visiting tourists, have been decreasing in Florida Keys National Marine Sanctuary since the 1990s (Leeworthy 1996, Leeworthy et al. 2010, Leeworthy and Morris 2010).
Despite the human population decrease and overall reduction in fishing in the Florida Keys since the 1990s, heavy recreational and commercial fishing pressure continues to suppress biodiversity, affecting the abundance and distribution of key species (see Question 12). Fishing stress can disrupt living resource quality by removing ecologically important top-level predators and, therefore, shifting reef ecosystem dynamics (Frank et al. 2005).
Fishing methods can also impact living resource quality. For example, damage to the benthos can result when traps or mobile fishing gear, such as trawls, are used. Marine debris, in the form of derelict fishing gear, can destroy benthic organisms and entangle mobile fauna, including endangered species, such as manatees and sea turtles (Donohue et al. 2001). When combined with high wave energy, lost, or, "ghost" crab and lobster traps can damage corals, and sever sponges (Chiappone et al. 2005) over a large area due to trap movement in high-wind-induced wave events (Lewis et al. 2009). In a recent report by Miller et al. (2010), a survey in the Florida Keys generally found similar or greater amounts of marine debris, especially derelict fishing gear, in no-take zones, when compared to baseline data from 2000, 2001 and 2008. Entanglement and vessel strikes also pose a threat to marine mammals (such as dolphins and manatees) and sea turtles because they often inhabit overlapping fishing areas.
In addition to fishing threats, vessel groundings occur regularly within the sanctuary, causing measurable impacts to living resources. Since 1998, almost all groundings have involved small (<50 feet, or 15 meters), privately owned vessels. Groundings often result in significant injury to corals, seagrasses, and other benthic organisms (NOAA 2007). Furthermore, vessels that try to "power off" the grounding site can cause significantly more injury.
In the Florida Keys, the number of reported vessel groundings decreased annually from 2002 to 2006 (from 721 groundings in 2002 to 301 in 2006), but it is not possible to determine if this trend is a result of fewer boaters using the resource because of higher fuel costs, increased boater awareness of the sensitivity of the environment, or a reduced willingness to call for assistance if boaters run aground. Generally, there has been no proportional shift in impact to different living resource types: approximately 14% of groundings impact coral, an estimated 85% impact seagrasses, and about 1% impact hard-bottom habitat (Donahue et al. 2008). Because corals and seagrasses grow in shallow water they are also susceptible to a variety of other direct impacts from smaller commercial and recreational vessels such as damage from the propeller, hull, engine, and anchoring. Despite the fact that the number of reported vessel groundings in the Florida Keys is decreasing, anchor damage, groundings, and propeller scarring still occur frequently and often result in immediate resource devastation with long-term impacts (Farrer 2010).
From the beginning of 1994 through 2010, the Florida Department of Environmental Protection reported approximately 2,500 incidents of spills in the Florida Keys. The annual mean number of petroleum and chemical spills was around 150 over the same period, with diesel fuel, motor oil, and gasoline representing 49% of these incidents, collectively. Spills in the sanctuary can have an impact on living resource quality. Whether associated with fuel discharges from small vessel groundings, or larger oil or chemical spills resulting from offshore shipping traffic, offshore drilling operations, or land-based sources, spills have the potential to adversely impact corals, foraging birds, marine mammals, fishes, seagrasses and mangroves.
Diver impacts from recreational snorkeling or scuba diving can negatively impact corals in locations that are heavily utilized. Other ecotourism activities in the Florida Keys, such as dolphin-watching boats, can disrupt natural activities of these animals.
Even though the human population recently decreased in the Florida Keys, indirect impacts from urbanization and use of coastal areas will continue to impact living resource quality. Runoff from nonpoint sources of pollution diminishes water quality. Illegal discharges (e.g., discharging or depositing sewage into all waters) can also create excessive amounts of nutrients, stimulating the rapid growth of algae, which in turn smother and kill live coral.
Both direct and indirect impacts can adversely affect living resource quality in the Florida Keys. However, over the long term, localized direct impacts may be overwhelmed by the adverse and wide-ranging indirect effects of anthropogenically caused climate change resulting in sea level rise, abnormal air and water temperatures, and changing ocean chemistry.
Living Resources and Trends
Status: Good Good/Fair Fair Fair/Poor Poor Undet.
Trends:
▲ Conditions appear to be improving.
- Conditions do not appear to be changing.
▼ Conditions appear to be declining.
? Undeterminted trend.
N/A Question not applicable.
# |
Status |
Rating |
Basis For Judgement |
Description of Findings |
9. |
Biodiversity |
|
Relative abundance across a spectrum of species has been substantially altered, with the most significant being large reef-building corals, large-bodied fish, sea turtles, and many invertebrates, including, the long-spined sea urchin. Recovery is questionable. |
Selected biodiversity loss has caused or is likely to cause severe declines in some but not all ecosystem components and reduce ecosystem integrity.
|
10. |
Extracted Species |
?
|
Historical effects of recreational and commercial fishing and collection of both targeted and non-targeted species; it is too early to determine ecosystem effects of new fishery regulations and new ecosystem approaches to fishery management. |
Extraction has caused or is likely to cause severe declines in some but not all ecosystem components and reduce ecosystem integrity.
|
11. |
Non-indigenous Species |
|
Several species are known to exist; lionfish have already invaded and will likely cause ecosystem level impacts; impacts of other non-indigenous species have not been studied. |
Non-indigenous species may inhibit full community development and function, and may cause measurable but not severe degradation of ecosystem integrity.
|
12. |
Key Species |
|
Reduced abundance of selected key species including corals (many species), queen conch, long-spined sea urchin, groupers and sea turtles. |
The reduced abundance of selected keystone species has caused or is likely to cause severe declines in ecosystem integrity; or selected key species are at severely reduced levels, and recovery is unlikely.
|
13. |
Health of Key Species |
|
Hard coral and gorgonian diseases and bleaching frequency and severity have caused substantial declines over the last two decades; long-term changes in seagrass condition; disease in sea turtles; sponge die-offs; low reproduction in queen conch; cyanobacterial blooms; lost fishing gear and other marine debris impacts on marine life.
|
The comparatively poor condition of selected key resources makes prospects for recovery uncertain.
|
14. |
Human Activities |
|
Despite the human population decrease and overall reduction in fishing in the Florida Keys since the 1990s, heavy recreational and commercial fishing pressure continues to suppress biodiversity. Vessel groundings occur regularly within the sanctuary. Annual mean number of reported petroleum and chemical spills were around 150 during that time period, with diesel fuel, motor oil, and gasoline representing 49% of these incidents collectively. Over the long term, localized direct impacts may be overwhelmed by the adverse and wide- ranging indirect effects of anthropogenic climate change resulting in sea level rise, abnormal air and water temperatures, and changing ocean chemistry. |
Selected activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem.
|
Maritime Archaeological Resources
The following information provides an assessment by sanctuary staff and experts in the field of the status and trends pertaining to the current state of sanctuary maritime archaeological resources:
15. What is the integrity of known maritime archaeological resources and how is it changing?
There is some uncertainty regarding the integrity of submerged maritime archaeological resources in Florida Keys sanctuary. Organic, ferrous, and other manmade materials associated with maritime archaeological resources (wood, iron, copper, brass, leather, twine, and fabric) are non-renewable resources. To varying extents, they are all subject to deterioration from corrosive and chemical reactions involving seawater (e.g., salts and oxygen), movement caused by storms, and marine life impacts (e.g., sea turtles scratching or cleaning their carapaces, stone crabs eating wood). Sediment movement can also affect resources by subjecting them to shifting foundations, exposure, or abrasion. Storms such as hurricanes can also influence resource integrity by covering or uncovering resources with sediment. In addition, looters have been taking artifacts from archaeological sites in the Keys for many years. Because of these factors, the rating for this question is "fair/poor" because the diminished condition of selected archaeological resources has substantially reduced their historical, scientific or educational value and is likely to affect their eligibility for listing in the National Register of Historic Places. The trend rating is "declining" because anecdotal evidence suggests human impacts to maritime archeological resources has increased in the form of recreational and commercial fishing gear entanglement and multiple reported vessel groundings that occur on or near maritime archeological resources.
16. Do known maritime archaeological resources pose an environmental hazard and is this threat changing?
No environmentally dangerous levels of hazardous material leakages have occurred in association with any maritime archeological resources in the sanctuary; however, some maritime archeological resources have been dislodged and fragmented during storm events. These fragments and pieces have the potential to come into contact with and impact the surrounding habitat. Therefore, our rating for this question is "good/fair" because selected maritime archaeological resources may pose isolated or limited environmental threats, but substantial or persistent impacts are not expected. Furthermore, there is no evidence to suggest that the environmental threat of sanctuary maritime archeological resources is changing.
17. What are the levels of human activities that may influence maritime resource quality and how are they changing?
Volunteers with the Florida Keys National Marine Sanctuary Submerged Resources and Inventory Team have documented more than 400 underwater historical sites in the sanctuary, and it is assumed there are many resources yet to be discovered and documented. More than 300 vessel groundings are reported in the sanctuary every year and some may impact maritime archaeological resources. In addition, the availability of inexpensive, off-the-shelf underwater technologies now affords the public the opportunity to locate and visit archaeological resources, thus increasing the potential for looting and other unauthorized human activities that can further affect the rate of deterioration and scientific value of maritime archaeological resources in the sanctuary. In addition, hook-and-line and commercial fishing tackle are also regularly found on submerged resources. Because reports of looting and vessel grounding cases involving potential maritime archaeological resources are increasing, the response to this question is rated "fair/poor" as these activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem. Although the intensity of these impacts varies year-to-year, the resulting trend suggests that conditions appear to be "declining."
Maritime Archaeological Resources and Trends
Status: Good Good/Fair Fair Fair/Poor Poor Undet.
Trends:
▲ Conditions appear to be improving.
- Conditions do not appear to be changing.
▼ Conditions appear to be declining.
? Undeterminted trend.
N/A Question not applicable.
# |
Status |
Rating |
Basis For Judgement |
Description of Findings |
15. |
Integrity |
| Resources are non-renewable and are subject to deterioration or loss resulting from looting, chemical processes, shifting sediments, marine life, fishing gear entanglement and vessel groundings (the last two are increasing in frequency). |
The diminished condition of selected archaeological resources has substantially reduced their historical, scientific, or educational value and it likely to affect their eligibility for listing in the National Register of Historic Places. |
16. |
Threat to Environment |
|
Movement of sunken vessels during storm threatens nearby resources. |
Selected maritime archaeological resources may pose isolated or limited environmental threats, but substantial or persistent impacts are not expected. |
17. |
Human Activities |
|
Reports of looting and vessel grounding cases involving potential resources are increasing. |
Selected activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem. |
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