Marine Debris
Hawaiian Islands Humpback Whale

Why is it a concern?

Each year, tons of marine debris drift through the waters surrounding the Hawaiian Islands and wash onto shorelines, posing a threat to humpback whales, Hawaiian monk seals, sea turtles, seabirds and other wildlife through entanglement or ingestion. The debris, including but not limited to ropes, cargo nets and derelict fishing gear, significantly damages seafloor habitat and important species including coral and algae as it washes over the reefs. While some of the marine debris is generated from land-based sources (e.g., storm water runoff, dumps and landfills, streams, sewer overflow, storm drains, and litter), marine-based sources (e.g., trawl nets, gill nets and other lost or discarded fishing gear) can produce substantial amounts of debris that may cause significant damage to the coral reefs of Hawai‘i and pose serious threats to marine mammals and other organisms. The impacts of marine debris are particularly apparent because atmospheric and oceanographic forces cause ocean surface currents to converge on Hawai‘i, bringing a vast amount of debris floating throughout the North Pacific to the islands.

In the Hawaiian Islands Humpback Whale sanctuary, entanglement in marine debris has been widely identified as a primary cause of human-caused mortality for humpbacks. Recent studies suggest that entanglement might be responsible for a 3.7 percent annual mortality for humpback whales off the northeastern United States, and North Pacific humpbacks have recently been shown to have entanglement scar rates that are comparable to this population.
Marine mammal entanglement in marine debris is a significant threat to the central North Pacific stock of humpback whales migrating to Hawai‘i each winter. Recent analyses of entanglement scarring from the SPLASH project (Structures of Population, Levels of Abundance and Status of Humpback Whales) indicate that almost 40 percent of the Hawaiian population have been entangled at least once in their lives. Since 2002, the sanctuary has received more than 144 reports of whales entangled in gear. A total of 83 reports were confirmed as truly involving entangled humpback whales, representing as many as 57 different animals. The actual number of entangled whales is likely to be considerably higher, as many go undetected or unreported.

Overview of Research

The Hawaiian Islands Humpback Whale National Marine Sanctuary is actively seeking research partners to conduct work connected to Marine Debris as a sentinel issue.

Science Needs and Questions

• What is the magnitude and impact of entanglement to the central North Pacific stock of humpback whales?
• What is the best and most appropriate level of response towards freeing animals and gaining information while reducing risk for animals and humans?
• What are the best means – methodology and equipment, to gain information on large whale entanglement threat?
• How can entanglement data be interpreted towards reducing entanglement threat for humpback whales in Hawaii, as well as for other species worldwide, while considering human stakeholders (e.g. tour and fishing industry)?
• What are effective mitigating measures, and are these measures without peripheral risks (e.g. pingers), productive, and feasible?

Education and Outreach Material

Marine Debris in the Hawaiian Islands Humpback Whale Sanctuary one pager

Marine Debris in Hawaii Brochure

NOAA Marine Debris Program Education Materials

References

Gittings, S.R., M. Tartt, and K. Broughton. 2013. National Marine Sanctuary System Condition Report 2013. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Office of National Marine Sanctuaries, Silver Spring, MD. 33 pp.

Lyman, E. 2009. A preliminary investigation of gear entangling humpback whales, Megaptera novaeangliae, in the North Pacific. In: Symposium on the results of the SPLASH humpback whale study; Final report and recommendations. Calambokidis, J. (Ed.). pp 20-22.

NOAA (National Oceanic and Atmospheric Administration). 2008. Marine Debris Emergency Response Planning in the North-Central Gulf of Mexico Interim Draft Report. 44pp.

ONMS (Office of National Marine Sanctuaries). 2010. Hawaiian Islands Humpback Whale National Marine Sanctuary Condition Report 2010. U.S. Department of Commerce, National Oceanic and Atmospheric Administration, Office of National Marine Sanctuaries, Silver Spring, MD. 63 pp.

Robbins, J. 2009. Entanglement scarring on North Pacific humpback whales. In: Symposium on the results of the SPLASH humpback whale study; Final report and recommendations. Calambokidis, J. (Ed.). pp18-19.