Threatened and Endangered Species - Status Reports
Date Published: February 2017
Number of Pages: 25
Author(s): Chris L. Sato
The leatherback sea turtle has been listed as a state endangered species in Washington since 1981. Seven populations are recognized globally according to the location of nesting regions. This periodic status review will focus on the western Pacific leatherback sea turtle population, which is the population occurring in Washington.
Members of the western Pacific population migrate from nesting sites in the western Pacific (Indonesia, Papua New Guinea, Solomon Islands, and Vanuatu) to forage in coastal waters off Washington, Oregon and California from summer through fall. The trans-Pacific journey of over 10,000 km (one-way) spans the exclusive economic zones of multiple Pacific nations and international waters, and requires roughly one year to complete. The leatherbacks’ arrival coincides with the development of seasonal aggregations of their preferred prey, jellyfish and other softbodied organisms.
Globally, the leatherback sea turtle population has declined 40 percent since the mid-20th century. Although size of the western Pacific population is unknown, the population is estimated to have declined over 80 percent in the same period of time, primarily due to: human harvest and animal predation of eggs, hatchlings and adults at nesting sites, fisheries bycatch, ingestion of and entanglement in human-related marine debris, and tidal inundation of nests. The western Pacific leatherback sea turtle regularly occurs in Washington’s coastal and shelf waters. Although there are only 78 documented records, abundance has undoubtedly declined as noted for the entire western Pacific population.
Various regulations and management activities implemented by federal, international, and nongovernmental entities directly or indirectly benefit western Pacific leatherback sea turtles. These include federal designation of critical habitat along portions of the U.S. West Coast, including all of Washington’s outer waters; regulation of commercial fisheries to reduce incidental bycatch of leatherbacks; establishment of conservation areas and stranding and disentanglement networks; and projects to monitor and protect against harvest at nesting beaches in Indonesia. Nonetheless, serious threats to the western Pacific leatherback sea turtle span coastal terrestrial, pelagic and nearshore habitats across the Pacific Ocean.
Because the threats to the western Pacific population have not abated, the IUCN has predicted a total decline of 96 percent from historical levels by 2040.
For these reasons, it is recommended that the leatherback sea turtle remain listed as a state endangered species in Washington.
Sato, C. L. 2017. Periodic status review for the Leatherback Sea Turtle in Washington. Washington Department of Fish and Wildlife, Olympia, Washington. 20+iii pp.
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