State of Sanctuary Resources
This section provides summaries of the condition 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 National Marine Sanctuary System’s mission, and a system-wide monitoring framework (National Marine Sanctuary Program 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 responses to the questions found in this report are based primarily on the effects or potential effects of pressures on the sanctuary as they relate to humpback whales and their habitat, which are the current responsibilities of the Hawaiian Islands Humpback Whale National Marine Sanctuary. With one exception (Question 3), they do not address concerns or resources over which the sanctuary does not have authority or other responsibility.
The questions are meant to set the limits of judgments so that responses can be confined to certain reporting categories that will later be compared among all sanctuary sites and combined. The Appendix (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. 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 healthy 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
1. Are specific or multiple stressors, including changing oceanographic and atmospheric conditions, affecting water quality?
Because water quality problems observed in some nearshore waters of the sanctuary do not appear to have affected the majority of sanctuary waters or the humpback whales inhabiting these waters, the response to this question is rated as "good" and "not changing."
Broad global issues such as climate change, storm intensity and natural variations in weather patterns, as well as regional and localized anthropogenic impacts, have all threatened water quality in Hawai'i. As populations of humans grow in coastal areas, the use of the surrounding land increases, and thus the threat of land-based impacts may increase. Marine debris, sedimentation, freshwater input and biological contaminants all threaten coral reefs. Waters within and adjacent to the sanctuary are vulnerable to these issues; however, available information suggests that sedimentation, eutrophication, algal blooms and biological contaminants have been reported to be of primary concern (Draut et al. 2009).
The majority of water quality issues in Hawai'i occur in nearshore waters. For example, sediment deposition, retention and naturally driven resuspension (as well as associated contaminants) may be a concern in the coastal waters of northern Kaua'i (Draut et al. 2009), southeast O'ahu (Wolanski et al. 2009), western Maui and southern Moloka'i (Field et al. 2008). However, although there is the possibility that poor water quality in the coastal zone could impact mothers and their calves that occasionally utilize this area, actual impacts to humpback whales have not been documented by the sanctuary (Animal in Distress Database and E. Lyman, HIHWNMS, pers. comm. 2010).
Ocean acidification and increasing water temperature (Würsig and Gailey 2002) have been identified as issues which may affect changes in water quality, but have not been systematically assessed.
2. What is the eutrophic condition of sanctuary waters and how is it changing?
Similar to Question 1, eutrophication and associated benthic algal blooms observed in some nearshore waters of the sanctuary do not appear to have affected the majority of sanctuary waters or the humpback whales inhabiting these waters. Therefore, the response to this question is rated as "good" and "not changing."
Chronic nutrient enrichment and potentially associated planktonic and/or benthic algal blooms are known to occur in some nearshore areas with groundwater input to sanctuary waters. For example, in the coastal waters of Maui, macroalgal blooms (of both native and alien invasive species) occur in areas where there is substantial human-caused nutrient input originating from sources such as wastewater effluent from injection wells, leaking or failing wastewater disposal systems or cesspools, and runoff from agricultural fertilizers (Smith et al. 2005, Dailer et al. 2010). Algal overgrowth and other competitive interactions have led to geographically isolated shifts in dominance in benthic assemblages. Nutrient enrichment is likely a major factor driving these changes. Although little work has been done to assess the impacts of eutrophication on water column productivity in Hawai'i, nutrient enrichment may contribute to stimulating harmful algal blooms, which can affect human health via fish consumption. There is hope that recent changes in agricultural practices and improvements in wastewater treatment and disposal (e.g., large capacity cesspools were banned in 2006 by the state of Hawai'i) will limit the future extent of these threats.
While increases in harmful algal blooms have been linked to increases in marine mammal disease and mortality elsewhere (Gulland and Hall 2007), these events have been associated with biotoxins transferred in the food web. Because humpback whales do not feed while in Hawaiian waters, they are not likely to be impacted by local algal blooms via diet, though the impacts from incidental ingestion are unknown.
3. Do sanctuary waters pose risks to human health?
Although occasional closures of some nearshore swimming areas occur due to pollutant concentrations that may adversely affect human health, the response to this question is rated as "good/fair" and "not changing" because beach closures have had a limited effect on access to sanctuary resources, and there is no evidence to suggest that these conditions are changing. It is important to note, however, that water quality monitoring data are limited or lacking in many streams and coastal segments, and most offshore areas of the sanctuary. Additionally, water quality issues such as polluted runoff, injection wells and vessel discharges have raised concerns of ocean users.
Improving Water Quality
From approximately the 1950s to the 1970s poorly treated sewage was discharged on the shallow offshore areas of Sand Island (Dollar 1979) and in Kaneohe Bay (Smith et al. 1981). In the 1980s Hawai'i took significant action to improve coastal water quality by removing most wastewater outfalls from bays and shallow waters. Moving sewage outfalls to deeper offshore waters (approximately 40 -75 m (130 - 250 ft)) has allowed for significant recovery to the previously stressed areas (Smith et al. 1981, Dollar and Grigg 2003)
Water quality at beaches in Hawai'i is monitored by the Department of Health (DOH) for bacteria that would indicate a risk to human health. The DOH regularly monitors ocean and stream water, focusing on recreational waters where people swim and play, for the indicator bacteria Enterococcus spp. and Clostridium perfringens. Levels of these bacteria are used to detect the presence of human sewage in the water, which can result in gastrointestinal illnesses. In some cases, beach notification and closure decisions are made when samples exceed state water quality standards. However, in general, the DOH does not consider coastal waters with high levels of Enterococcus spp. to represent a threat to human health. This is because in tropical waters Enterococcus spp. may result from animal waste or soils, as well as human sewage (DOH 2008). In recent years, DOH has also collected data on turbidity, nutrients and chlorophyll at specified shoreline stations and in perennial streams. DOH uses these data, and other available data that meet specific quality criteria, to identify streams and coastal segments that are "water quality impaired" (e.g., where state water quality criteria are regularly exceeded). Turbidity is typically the most common pollutant to trigger a coastal water listing (DOH 2008).
In general, islands with larger population sizes have more water bodies where ambient pollutant concentrations regularly exceed state water quality criteria (Friedlander et al. 2005) (Table 1). In addition, pollutant concentrations normally decrease sharply with distance from shore, and offshore water quality is generally good. Impaired coastal waters as identified by the DOH are primarily harbors, semi-enclosed bays, and protected shorelines, where mixing is reduced and resident time of pollutants is long when compared with exposed coasts. Many bays outside the sanctuary that have coral reefs, such as Kāne'ohe Bay, Pearl Harbor (O'ahu), Nawiliwili Bay (Kaua'i) and Hilo Bay (Hawai'i), have been identified as impaired. The most widely distributed coastal pollutants are nutrients, sediments and Enterococcus spp (Friedlander et al. 2005).
Table 1. Number of water bodies by island where ambient pollutant concentrations regularly exceed State water quality criteria. ND = No data. (Source: Friedlander et al. 2005)
There is also concern about bacterial and biotoxicological contamination in fish intended for human consumption. In 1998, the DOH issued a fish and shellfish consumption advisory for all O'ahu urban streams (including those that drain into sanctuary waters). From 2003 to 2004, the DOH issued fish contamination advisories concerning high levels of mercury for 16 fish species in marine waters statewide. All of these fish consumption advisories remain in effect (see EPA National Listing of Fish Advisories). Ciguatera fish poisoning can result in gastrointestinal and neurological symptoms following the ingestion of fish containing ciguatoxin. The ciguatoxin responsible for this poisoning is produced by the benthic dinoflagellate Gambierdiscus toxicus, which lives freely and in association with various algae on coral reefs and hard surfaces in tropical waters (Hokama 1988). Ciguatera is the most common marine toxin poisoning worldwide, with more than 50,000 cases reported annually (Lehane and Lewis 2000). The incidence of ciguatera fish poisoning in Hawai'i is low, with approximately 3.6 cases per 100,000 people (Campora et al. 2010). The leeward coasts of the main Hawaiian Islands often report the majority of cases.
4. What are the levels of human activities that may influence water quality and how are they changing?
Because some human activities are known to have had localized impacts on water quality, the response to this question is rated as "good/fair." Management actions have reduced the levels or threats posed by some activities, while other activities primarily related to urbanization continue to increase. Therefore, the overall trend is rated as "not changing." Continued monitoring of water quality will be necessary to determine whether these trends are, in fact, offsetting.
Discharges that may directly affect water quality in sanctuary waters include vessels, a few mariculture facilities, a single sewage outfall (east of Honolulu), O'ahu municipal separate storm sewer systems, and other land-based point sources that have yet to be inventoried. Due to prevailing atmospheric circulation patterns, deposition of airborne chemicals at sea from global sources may be significant, as well. Dredging and trawling activities are of limited scope and generally occur well outside of sanctuary waters; and dredging operations are tightly regulated to minimize resuspension impacts. Human activities that generate nonpoint source diffuse pollution (e.g., groundwater-associated nutrient enrichment) and polluted runoff (during both dry and wet weather conditions) are of greatest overall concern due to their possible association with changes in water quality parameters such as temperature, salinity, pH, oxygen, light availability and nutrient levels; as well as bacterial contamination, toxic contamination, particulate loading, reef sedimentation and their combined impacts. Multiple bodies of water within and adjacent to sanctuary waters exemplify this, as water quality is impaired by excessive pollutants (see Question 1), according to the Hawai'i State Department of Health (DOH) and the U.S. Environmental Protection Agency (DOH 2008).
Increasing levels of urbanization are likely to lead to higher levels of point source (e.g., industrial facilities) and non-point source (e.g., deposition from fossil fuel burning) pollution. However, a reduction in the number of large cesspools (large capacity cesspools were banned in 2006 by the state of Hawai'i), and greater use of sewage pump-outs by vessels may help to reduce the input sources of sewage waste. The destructive terrestrial impacts of feral ungulates in Hawai'i remain a concern in upland ecosystems and to the associated watersheds.
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 |
|
Most areas with problems (e.g., sedimentation) are nearshore and restricted to bays and harbors; therefore, these issues are unlikely to pose threats to humpbacks. |
Conditions do not appear to have the potential to negatively affect humpback whales or habitat quality. |
| 2. |
Eutrophic Condition |
|
Locations with chronic nutrient enrichment and extensive algal blooms are limited to nearshore waters and may be increasing in extent or severity, but are not known to pose threats to humpbacks. |
Conditions do not appear to have the potential to negatively affect humpback whales or habitat quality. |
| 3. |
Human Health |
|
With the exception of occasional closures of some nearshore swimming areas, conditions are not currently believed to consistently adversely affect compatible uses of the sanctuary. |
Selected conditions that have the potential to affect human health may exist but human impacts have not been reported. |
| 4. |
Human Activities |
|
Numerous activities occur, but management actions have reduced some impacts; therefore, overall levels do not appear to be changing. |
Some potentially harmful activities exist, but they do not appear to have had a negative effect on water quality. |
Habitat
5. What is the abundance and distribution of major habitat types and how is it changing?
Due to the slowly increasing number of existing and proposed structures related to aquaculture and offshore energy production, and impacts associated with these facilities, the response to this question is rated as "good/fair" and "declining."
Humpback whales in the Hawaiian region prefer waters less than 180 meters (600 feet) in depth and are especially concentrated in waters with expansive shallow areas, typically with sandy bottoms and low rugosity (minimal variations in the seafloor habitat) (Herman et al. 1980, Mobley et al. 1999). There is evidence that shallow waters are preferred for calf rearing (Smultea 1994, Craig and Herman 2000). This habitat preference may be due to improved sound transmission and visual cues associated with animal interactions. Water clarity in both offshore and the preferred shallow-water habitat areas do not appear to have been significantly affected by human activities. However, an emerging issue that should be monitored is the increase in the number of existing and proposed structures related to aquaculture and offshore energy production. These structures should be monitored because they remove habitat in the water column and along the seafloor bottom that humpback whales prefer.
6. What is the condition of biologically structured habitats and how is it changing?
There are no biologically structured habitats that appear to be associated with or required by humpback whales in the sanctuary. For this reason, this question is not addressed.
7. What are the contaminant concentrations in sanctuary habitats and how are they changing?
Because there is no evidence that contaminants exist at substantial levels in humpback whales in Hawai'i, or in their habitats in the sanctuary, the response to this question is rated as "good" and "not changing."
Contamination resulting from pollutants could result in impaired immunity, increased susceptibility to disease, neurotoxicity, and reproductive impairment (Elfes et al. 2010) in marine mammals. However, studies conducted through theSPLASH project (see text box) have demonstrated that contaminants that are found in humpback whales are low and are assumed to have been acquired in their feeding grounds, particularly if the feeding grounds are near highly urbanized areas with inputs from treated municipal and industrial wastewater and stormwater discharges (Elfes et al. 2010). Hawaiian waters are not feeding grounds for humpbacks, and investigators are not concerned about this method of acquisition of toxicants by whales when they are in sanctuary waters. In addition, results from the SPLASH project found that these whales feed in Alaska and northern British Columbia, and they have the lowest levels of contaminants found in any humpback populations studied (Elfes et al. 2010).
Data on contaminants in humpback whale habitat in the Hawaiian Islands are limited. However, in a study testing the utility of semi-permeable membrane devices to monitor water quality, investigators found low concentrations of pesticides, including chlordane (an organochlorine pesticide), dieldrin (a persistent, bioaccumulative, toxic insecticide that was used from 1950 to 1974) and chlorpyrifos (an organophosphate insecticide), and low concentrations of polycyclic aromatic hydrocarbons (PAHs; a pollutant where some compounds can be carcinogenic or mutagenic) in nearshore waters off Maui adjacent to a large tract of agricultural land. The levels were considered unlikely to exert adverse effects on ecosystem resources (GERG 2001).
8. What are the levels of human activities that may influence habitat quality and how are they changing?
Due to human activities that have had, or are likely to have localized impacts on humpback whale habitats in the Hawaiian Islands, the response to this question is rated as "fair" and "declining".
There are a number of land- and ocean-based human activities in the Hawaiian Islands which may affect humpback whale habitats. On land, development in Hawaiian watersheds continues to increase. The impacts to the marine environment include those associated with runoff and its effects on water and habitat quality, as well as increased levels of contaminant delivery. Furthermore, patterns of runoff could be affected by the combined effects of increasing urbanization and greater acreage of fallow agricultural land (e.g., pineapple and sugarcane fields). In coastal and marine areas, activities that either do or could affect humpbacks and their habitats include high-speed ocean recreation activities, on-the-water whale watching, noise in the environment, vessel-whale collisions, and the use of acoustic-based monitoring by the military. Shifts in local habitat use by cows with calves have been noted and attributed to increasing coastal development and increasing use of high-speed boats, parasail boats and jet skis near shore (Glockner-Ferrari and Ferrari 1985, Forestell 1986).
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 |
|
Potential increase in the number of existing and proposed structures related to aquaculture and offshore energy production could remove humpback whale habitat in the water column and along the seafloor. |
Selected habitat loss or alteration has taken place, precluding full development of humpback whale assemblages, but it is unlikely to cause substantial or persistent degradation in humpback whale status. |
| 6. |
Structure |
N/A
|
There are no biologically structured habitats, such as coral reefs, that appear to be associated with or required by humpback whales in the sanctuary. |
N/A |
| 7. |
Contaminants |
|
The low levels of some contaminants in humpback tissues are believed to be acquired in feeding areas, not in the Hawaiian Islands. |
Contaminants do not appear to have the potential to negatively affect humpback whales. |
| 8. |
Human Activities |
|
Land and ocean-based activities including coastal development, high-speed ocean recreation activities, whale watching, underwater noise, vessel-whale collisions, and military activities. |
Selected activities have resulted in measurable habitat impacts, but evidence suggests effects are localized, not widespread. |
Living Resources
9. What is the status of biodiversity and how is it changing?
The Hawaiian Islands Humpback Whale National Marine Sanctuary is currently responsible for managing humpback whales and their associated habitat. The issue of biodiversity is not relevant at this time. For this reason, this question is not addressed..
10. What is the status of environmentally sustainable fishing and how is it changing?
Experts involved in evaluating resources of the sanctuary were of the opinion that this question is not relevant to the status of humpback whales and their habitat. For this reason, this question was not addressed.
11. What is the status of non-indigenous species and how is it changing?
The response to this question is rated as "good" and "not changing" because there are no known instances of non-indigenous species impacting or being affected by Pacific humpback whale populations in Hawai'i. Non-native species do occur in Hawaiian waters (primarily invertebrates), but they do not appear to have affected humpback whale habitats, nor do they interfere with the health or activities of whales in any known way.
12. What is the status of key species and how is it changing?
Considering historical reductions in the abundance of humpback whales, and recent data showing measurable increases, the response to this question is rated as "good/fair" and "improving" because the abundance and recruitment of North Pacific humpbacks is increasing.
SPLASH
The Structure of Populations, Levels of Abundance and Status of Humpbacks (SPLASH) represents one of the largest international collaborative studies of any whale population ever conducted and is the most comprehensive humpback whale research study ever undertaken for any population of whales in any ocean. The primary objectives of the SPLASH project are to improve the description of the stock structure of humpback whales in the North Pacific, to understand the abundance, trends and movements of these stocks, and to assess the human impact on them. The program is a cooperative effort of researchers from over 50 research groups in 10 countries, including the United States, Canada, Mexico, Japan, Russia, Philippines, and Central America. Data is primarily collected through photo-identification of whale flukes and genetic analysis of tissue samples in the humpback whales' breeding and feeding grounds. The Hawaiian Islands Humpback Whale National Marine Sanctuary has played a central role in initiating, funding and coordinating this project.
Humpback whales (Megaptera novaeangliae) were hunted commercially in the North Pacific until prohibited by the International Whaling Commission in 1966. Currently, humpback whales remain listed as "endangered" under the Endangered Species Act, and are designated as "depleted" under the Marine Mammal Protection Act. As a result, the central North Pacific humpback whale stock (the population in Hawai'i) is classified as a strategic stock3 by the NOAA National Marine Fisheries Service (Angliss and Lodge 2003). It is difficult to determine the degree to which they have recovered from whaling because of the lack of accurate abundance estimates, both before and immediately after whaling (Calambokidis et al. 2008). North Pacific humpback whale populations were thought to have numbered about 15,000 prior to commercial exploitation in the 20th century, although this was only a rough calculation based on whaling data that may have been inaccurate (Rice 1978). Following the cessation of commercial whaling, population size was estimated to be between 1,000 and 1,400 individuals (Table 2) (Gambell 1976, Johnson and Wolman 1984), although the methods used for these estimates are uncertain and their reliability has been questioned (Calambokidis et al. 2008).
Table 2. Estimates of annual increases in humpback whale abundance based on comparison of SPLASH study to previous estimates with similar methods. Note that "NPAC" stands for North Pacific and "Rice" refers to his 1978 study. (Source: Calambokidis et al. 1997)
Data collected between 1990 and 1993 yielded estimates of approximately 6,000 humpback whales in the North Pacific (4,000 for Hawai'i, 1,600 for Mexico and 400 for Japan) (Calambokidis et al. 1997). In an attempt to effectively understand the current population level of humpback whales, a highly migratory species, the SPLASH project was developed (Structure of Populations, Levels of Abundance and Status of Humpbacks, see text box). Recent analyses from theSPLASH project show that migratory movements and population structure of humpback whales in the North Pacific are highly complex. An overall pattern shows that the wintering areas off Hawai'i are the primary wintering regions for the more central and northern latitude feeding areas (Calambokidis et al. 2008).
Results from the SPLASH project also demonstrate that the current abundance of humpback whales is estimated to be approximately 20,000 for the entire North Pacific with over 50 percent of this population estimated to winter in Hawaiian waters (Calambokidis et al. 2008, Calambokidis 2009). It is important to note that single individuals may stay in Hawaiian waters for as little as two weeks during the approximately six-month whale season (Mate et al. 1998, Craig et al. 2001). Therefore, at any one time, the abundance of humpback whales in Hawai'i is less than the total population size. Analyses from the SPLASH project suggest that the population of humpback whales for the overall North Pacific has shown a 4.9 percent annual increase since the 1990-1993 population estimates and a 6.8 percent annual increase over the 44-year period since the end of commercial whaling for humpbacks in 1966 when the population was estimated to be between 1,000 and 1,400 individuals (Gambell 1976, Johnson and Wolman 1985, Calambokidis et al. 2008, Calambokidis 2009). For Hawai'i specifically, trends since the early 1990s show an annual rate of increase of approximately 6 percent (Mobley et al. 1999, Mobley et al. 2001, Calambokidis et al. 2008). While there is some uncertainty over historic populations of humpbacks in Hawaiian waters, as well as debate over whether humpback whales migrated to the waters they currently use in Hawai'i prior to 200 years ago (Herman 1979), there is convincing evidence of increasing abundance basin-wide in the North Pacific Ocean (Calambokidis et al. 2008).
It should be noted that new methods for estimating pre-whaling populations (Roman and Palumbi 2003) suggest that the methods used by Rice (1978) and others may have underestimated the pre-whaling population by an order of magnitude. Rice (1978) estimated that intensive commercial whaling removed more than 28,000 individuals from the North Pacific during the 20th century. This mortality estimate likely underestimates the actual kill as a result of under-reporting of Soviet catches (Yablokov 1994). Nevertheless, it is still estimated that the population currently appears to be increasing at a rate of about 6 percent per year (Calambokidis et al. 2008).
Increases in the abundance of humpback whales in the North Pacific could also affect the status of other species. For example, some species can feed on dead or dying newborn, juvenile or adult whales. Tiger sharks have been observed on numerous occasions preying on whales in the Hawaiian Islands over the last few years. Higher levels of humpback whale mortality (which accompanies higher population levels) results in an increase in the amount of whale biomass that can serve as a food source for benthic and pelagic organisms and marine bird communities. Other materials such as skin sloughing off the animals or placental remains are also density-dependent, and can serve as food for other species. Studies on these processes have not been conducted in the sanctuary; however, Antonelis et al. (2007) estimated that through all of these pathways, humpback whales currently represent a significant positive contribution of biomass to the ecosystem.
13. What is the condition or health of key species and how is it changing?
Because of the high number of injuries and scars caused by entangling gear, debris and contact with vessels on whales, as well as the effects of these impacts on their behavior (e.g., swimming, courting, calving, nursing, etc.), the response to this question is rated as "fair" and "declining."
Entanglement in fishing gear is a known source of injury and mortality for humpback whales in Hawai'i and elsewhere throughout their range in the North Pacific (NMFS 1991, Robbins 2009, Lyman 2009). Entanglement can result in abrasions, lesions, debilitating injury or even death depending on the type, amount and location of entangled gear. Entanglement (in addition to ship strikes) has been implicated in up to 60 percent of known humpback mortalities, and may be causing an annual mortality of up to 5 percent of the population (Wiley et al. 1995, Volgenau et al. 1995). Even without injury, entanglement can impair swimming and feeding ability, leading to isolation of individual members from groups, and/or metabolic stress. Presumably, stressed animals would also likely alter normal behaviors associated with courting, breeding, giving birth and nursing their young (Robbins 2010).
Figure 16. Frequency of entanglement injuries across North Pacific breeding grounds (bars). Sample sizes shown in white. Blue bars with 95% confidence intervals (vertical lines) were areas with sample sizes adequate for regional comparisons. (Source: Robbins 2009)
Marine debris and active fishing gear that can lead to whale entanglement may originate from both local and non-local sources. For example, some may originate from the summer feeding grounds and may include traps with lines and surface floats and nets (e.g., trawls, gill nets). Gear might also be encountered during migration, where it collects along oceanic fronts (where debris carried from around the North Pacific accumulates). While methods are available to measure scars and other indications of physical and behavioral impacts by entanglement, it is more difficult to determine specifically to what extent these and other stressors are affecting the health of the whales. The sanctuary currently works in collaboration with both private and federal agencies to develop methods to assess these impacts through established techniques such as biopsy tissue sampling and experimental techniques such as visual assessment measures, skin collection and breath collection (the collection of respiratory gases from free-swimming humpback whales in order to determine metabolic state, or any abnormal conditions including evidence of disease).
The frequency of entanglement events, regions of concern and impacts to populations are not yet fully known. This is because the rates at which events are reported depend on several factors, including the actual number of events, the likelihood of event detection, and observer awareness and willingness to report (Robbins and Mattila 2004). As part of the SPLASH project, systematic sampling and scar interpretations were performed to provide insight into these issues across the North Pacific Ocean (Robbins 2009). Although sample sizes were not sufficient to rigorously compare all breeding grounds, results indicate that Hawai'i was not significantly different from other breeding grounds (Figure 16). Results also demonstrated that entanglement rates are higher in coastal feeding areas, particularly in the Eastern North Pacific, when compared to breeding areas.
Figure 17. Of the gear identified, most (76 percent) reported entangling humpback whales in the eastern North Pacific involved passively set, fixed fishing gear, like pots (traps) and gillnets. (Source: Lyman 2009)
Lyman (2009) assessed confirmed reports of large whale entanglement incidences in order to determine the frequency of entanglements and the types of gear found entangling humpback whales within much of the eastern and central North Pacific, before, during and after the SPLASH project. Results indicate that from the time period studied (2001 - 2009) there were 52 confirmed reports of entangled humpback whales in Hawai'i, averaging 5.8 cases yearly. Of the gear that was identified on entangled humpback whales in the eastern North Pacific, most (76 percent) involved passively set, fixed fishing gear, such as pots (traps) and gillnets (Figure 17). Also, some of the gear found entangling humpback whales was carried over long distances. For example, gear recovered and/or documented from eight entangled humpbacks within the Hawai'i breeding grounds came from Alaska or British Columbia. Seven of these reports were pot gear from crab, fish and shrimp fisheries. The average minimum straight-line distance the gear was carried was 4,030 kilometers (2,500 miles), with the longest distance being 4,540 kilometers (2,820 miles), involving a shrimp pot set near Wrangell, Alaska, that was later removed from the animal off Maui. Six percent of all confirmed reports of entangled humpback whales involved mortality. The most lethal gear based on reports received and ability to confirm type was seine gear, with gillnet and pond gear being the next deadliest gear types. It should be noted that sample sizes were small across all gear types.
Vessel traffic creates the potential for collisions with humpback whales. Over the last decade, the number of reports involving confirmed vessel-whale collisions has increased, likely the result of increased awareness from boat operators. While it is difficult to gauge the percentage of vessel-whale collisions that are reported to the media and authorities, it is clear that not all incidents are reported. Lammers et al. (2003) have documented that the annual number of confirmed collision reports has generally increased over the past 20 years; however, there is currently insufficient data to confirm whether collisions between whales and vessels have actually increased, or if the increasing number of reports is due to increased awareness and reporting. At least 10 collisions occurred in Hawai'i from 1998 to 2004, including five that resulted in the death of or serious injury to the whales. From 2005 through the end of the 2010 whale season, at least 42 confirmed collisions occurred, with at least 14 animals showing signs of injury (Lammers et al. 2003, Lyman 2010). Vessel-whale collisions also have serious safety consequences for vessel operators and their passengers. For example, in 2003, a three-year-old boy was killed when the tour boat his family was on struck a whale off O'ahu. Serious damage to vessels can also result from vessel-whale collisions. In 2006, after colliding with at least one humpback off Maui, a large whale watching vessel required extensive repairs to its steering and propulsion systems.
Contamination resulting from pollutants is also a cause of concern for the health of marine mammals and other top-level predators. Persistent organic pollutants (POPs) entering the marine environment are absorbed by organic matter and are taken up by plankton at the base of marine food webs. Bioaccumulation of POPs through the food chain is of concern, particularly for long-lived, top-level predators including marine mammals. POP contamination could result in impaired immunity, increased susceptibility to disease, neurotoxicity, and reproductive impairment (Elfes et al. 2010). Studies conducted through the SPLASH project (see text box) have demonstrated that contaminants that are found in humpback whales are low and are assumed to have been acquired in their feeding grounds, particularly if the feeding grounds are near highly urbanized areas with inputs from treated municipal and industrial wastewater and stormwater discharges (Elfes et al. 2010). Hawaiian waters are not feeding grounds for humpbacks, and investigators are not concerned about this method of acquisition of toxicants by whales when they are in sanctuary waters. In addition, because humpbacks and other baleen whales feed on small organisms, they are believed to be at a much lower risk of ingesting contaminants than toothed whales, which feed on organisms with higher levels of bioaccumulated contaminants (Clapham et. al. 1999). For these reasons, the sanctuary does not currently conduct regular assessments of contaminant or pathogen levels in humpback whales in Hawai'i. However, the SPLASH project found that the humpback whales that visit Hawai'i feed in Alaska and northern British Columbia, and they have the lowest levels of contaminants found in any humpback populations studied (Elfes et al. 2010).
14. What are the levels of human activities that may influence living resource quality and how are they changing?
Due to reports of entanglement and whale-vessel collisions, as well as emerging issues such as existing and proposed nearshore development activities, some of which occur outside of Hawaiian waters, the response to this question is rated "fair/poor" and is considered to be "declining."
The challenge in addressing the issue of entanglement in both fishing gear and marine debris (see Question 13) is that the majority of marine debris and entanglement incidents may originate in places outside Hawaiian waters (Lyman 2009). Entanglement and marine debris also pose a threat to other marine mammals, sea turtles and birds. Humpback whales are especially vulnerable because they often transit and inhabit regions with growing amounts of both fishing gear and debris. It has been estimated that more than 300,000 whales, dolphins and porpoises die every year as "bycatch" or become entangled (Read et al. 2006). Together, entanglement and ship strikes have been implicated in up to 60 percent of known humpback mortalities, and may be causing an annual mortality of up to 5 percent of the population (Wiley et al. 1995, Volgenau et al. 1995, Robbins et al. 2009).
Reports of whale-vessel collisions have also increased over the last decade. The higher speed and number of vessels both large and small, combined with the increasing population of humpback whales, makes collisions more and more likely, and potentially more lethal (Laist et al. 2001) for whales and ocean users. Ships also affect the acoustic environment of the ocean, resulting in an uncertain level of impact on species like humpbacks, which are highly dependent on vocalization for communication and feeding.
It is unclear what level of impact might be associated with an increasing number of aquaculture facilities. Beyond the risks of entanglement and habitat loss, further study is necessary to determine how humpbacks might be affected.
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 |
N/A
|
The sanctuary is currently responsible for managing humpback whales and their associated habitat. The issue of biodiversity is not relevant at this time. |
N/A
|
| 10. |
Extracted Species |
N/A
|
Extraction is not relevant to the status of humpback whales and their habitat. |
N/A |
| 11. |
Non-indigenous Species |
|
There are no known non-indigenous species that affect humpback whales or their habitats. |
Non-indigenous species are not suspected or do not appear to affect status of humpback whales. |
| 12. |
Key Species |
|
Humpback whale population levels are still below historic estimates in the North Pacific; however, recent estimates indicate humpback whale population levels in Hawai'i have increased by 6 percent annually. |
Selected key or keystone species are at reduced levels, perhaps precluding full community development and function, but substantial or persistent declines are not expected. |
| 13. |
Health of Key Species |
|
Increased reported numbers of vessel collisions and entanglements and associated impacts (e.g., lesions and impairment of movement and other behaviors). |
The diminished condition of selected key resources may cause a measurable but not severe reduction in ecological function, but recovery is possible. |
| 14. |
Human Activities |
|
Increased reported numbers of collisions and entanglements (often including fishing gear encountered elsewhere). |
Selected activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem. |
Maritime Archaeological Resources
15. What is the integrity of known maritime archaeological resources and how is it changing?
The response to this question is rated as "fair" and "declining" because of the gradual loss of integrity of maritime archaeological resources due to natural and human impacts. These impacts include various factors of natural deterioration, as well as both inadvertent and intentional damage from human impacts.
The sanctuary does not have jurisdiction over maritime archaeological resources, but the sanctuary system, through the Pacific Islands Region office, is assisting in surveying and monitoring some of these resources to a limited extent. Further, part of the sanctuary mission is to "facilitate uses compatible with the primary purpose of resource protection, including those traditional and customary uses of native Hawaiians." For these reasons, it is important to monitor the integrity of these resources.
Maritime archaeological resources in the marine environment are subject to different rates of deterioration from biological, chemical and mechanical processes. Organic material (wood in particular) is subject to internal bacterial decay, and in warm marine waters provides food for the shipworm (Teredo navalis); therefore, exposed wooden ship components on historic sites are rare, and only exist buried in sediments. Most of the historic shipwreck sites within the sanctuary feature iron or steel elements (e.g., hull, engine, boiler components, etc.). These ferrous metals are subject to chemical deterioration through the corrosion process; however, over time, ferrous artifacts become encrusted by sediment or coralline algae and other marine organisms, and this barrier greatly slows the rate of chemical deterioration. Mechanical deterioration, through the processes of surface wave, storm surge and hurricane impacts, can affect both buried and exposed features of historic and archaeological resources. Historic wrecks in shallow waters are slowly broken up over time, with components often being washed up onto the shore (see Shipwreck Beach on Lāna'i). Local divers report that deeper sites, such as shipwrecks and aircraft in 25 to 30 kilometers (80 to 100 feet) of water, have been broken or moved by infrequent hurricane events. These natural processes are ubiquitous and, for the most part, not subject to practical remediation.
Human impacts to maritime archaeological resources fall into two categories: inadvertent and intentional. Inadvertent impacts include anchor and mooring damage and improper diving activities. Historic sites within the sanctuary show evidence of both. Popular dive sites without proper established moorings are subject to anchor damage. Divers who unwittingly "clean" wrecks remove the encrusted algae and sediment and initiate renewed corrosion. Possible inadvertent impacts include high sedimentation rates (possibly resulting from coastal development), which obscure coastal resources such as fishponds, and sand dredging for channel or beach replenishment projects, which (without proper archaeological surveys) can destroy resource sites. Intentional human impacts include the damage and removal of historic artifacts from shipwreck and aircraft sites. Unfortunately, despite existing state and federal laws to the contrary, there have been a number of known incidents of this sort within the sanctuary. For example, naval aircraft have been damaged by non-permitted commercial boat moorings attached to propeller shafts, cockpit instruments have been removed, 50-caliber machine guns have been illegally recovered, and compass housings have been taken from historic World War II landing craft. On steamship wreck sites, compasses have been removed, deck lights have been stolen, and brass and copper and bronze fittings have been looted.
A resource survey within the sanctuary is only in the preliminary stages, as the sanctuary does not have direct jurisdiction over maritime archaeological resources, and survey capacity is limited. However, enough information exists from the 25 located and visited historic sites (out of approximately 115 reported lost historic ships and aircraft) and the many archaeological sites of marine coastal Hawaiian fishponds (some 61 sites documented by the state) to indicate that these human and natural processes are affecting the integrity of the overall resource.
16. Do known maritime archaeological resources pose an environmental hazard and is this threat changing?
Because of a lack of information on the locations or threats posed primarily by World War II sunken vessels, both the status and trend for the response to this question is rated as "undetermined."
Maritime archaeological resources do not usually represent immediate threats to humpback whales and their habitat. In some cases, long term impacts from chemical leaching (e.g., iron from hulls) can occur, and there is the potential for World War II-era shipwrecks to release hazardous material such as fuel into the environment as they disintegrate. Neither has been quantified at the present time in the sanctuary due to the lack of survey data. Numerous ordnance or military munitions were lost in the area, but their locations and threat level within the sanctuary have not been assessed. At this time, there is no evidence that these submerged maritime resources impact the physiology or behavior of humpback whales in the Hawaiian waters.
17. What are the levels of human activities that may influence maritime resource quality and how are they changing?
In the sanctuary, many recreational divers responsibly visit and enjoy known shipwreck and historic aircraft wreck sites with minimal impact to the quality of the resources. However, due to the lack of resource preservation knowledge and resource protection, a few divers and boat operators apparently have damaged known sites. These impacts include the damage and removal of historic artifacts from shipwreck and aircraft sites. This, in combination with increased access to deeper sites provided by new diving technologies (e.g., technical mixed-gas diving and closed-circuit rebreathers), leads to the response of "fair/poor" and "declining" for this question. Greater access to deeper archaeological resources, given that these resources are not effectively managed or protected, may lead to increased inadvertent and intentional damage. Both of these kinds of impacts have already been documented within the sanctuary.
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 |
|
Gradual loss of maritime archaeological resource integrity due to natural and human impacts including biological, chemical and mechanical weathering; anchor and mooring damage; diver visitation; looting; sedimentation, etc. |
The diminished condition of selected archaeological resources has reduced, to some extent, their historical, scientific or educational value and may affect the eligibility of some sites for listing in the National Register of Historic Places. |
| 16. |
Threat to Environment |
?
|
Data on wrecks that may pose hazards are insufficient to determine status or trend. |
N/A |
| 17. |
Human Activities |
|
Increasing diving activity due to technical advances provides greater uncontrolled access. |
Selected activities have caused or are likely to cause severe impacts, and cases to date suggest a pervasive problem. |
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