Category: Status Reports
Published: February 2017
Author(s): Chris L. Sato
The green sea turtle and the loggerhead sea turtle have been listed as state threatened species in Washington since 1990. Both species make rare appearances along the outer coast of Washington, almost always observed as stranded individuals.
Green sea turtles occurring in Washington are members of the federally threatened East Pacific Distinct Population Segment (DPS). The likely origin of these individuals are nesting beaches in Mexico. Members of this DPS mostly inhabit the coastal waters, lagoons, and bays from San Diego, California, south to Peru and the Galapagos Islands. Although global population trends for the green sea turtle indicate an overall 48 to 67 percent decline in the number of nesting females over the past 100 to 150 years, nesting data for the East Pacific DPS indicate an increasing trend in recent decades, with a current estimate of 20,112 females recorded at 39 nesting sites along the western coast of Mexico.
Loggerhead sea turtles occurring in Washington are part of the federally endangered North Pacific DPS. This DPS migrates from nesting sites in Japan to forage in pelagic and coastal waters off the west coast of North America, mainly in Mexico and southern California, but rarely observed reaching Oregon and Washington. A substantial decline in the North Pacific DPS occurred over the last half of the 20th century and current nesting numbers represent a fraction of historical nesting levels. The estimated number of nests for this DPS averaged 9,050 nests per year from 2009 through 2013. Global population trends for this species indicate a decrease of 47% over the past 100 to 150 years.
Significant known threats to both the East Pacific green sea turtle DPS and North Pacific loggerhead sea turtle DPS are harvest of eggs, juveniles and adults; incidental capture in commercial and recreational fisheries; destruction and modification of nesting habitat; and marine debris. Sea turtles are also particularly vulnerable to climate change, which may impact all stages of their life histories.
Various regulations and management activities implemented by federal, international, and nongovernmental entities directly or indirectly benefit both of these populations. These include regulation of commercial fisheries to reduce incidental bycatch of sea turtles, establishment of conservation areas and stranding and disentanglement networks, and projects to monitor and protect nesting beaches in Mexico and Japan.
Despite the rarity of green sea turtles and loggerhead sea turtles in Washington, both are part of federally listed DPSs that face continuing conservation threats. Even the loss of a few individuals holds potential consequences when combined with other impacts. Both populations are wide-ranging and migratory, and threats are widespread across the nesting and marine portions of their ranges. Members of both populations spend the majority of their lives in areas outside of U.S. jurisdiction, so international cooperation is essential for addressing conservation challenges.
For these reasons, it is recommended that the green sea turtle remain listed as a state threatened species in Washington. It is also recommended that the loggerhead sea turtle be uplisted to an endangered species in Washington due to the threats outlined, the documented decline of the North Pacific DPS, and to reflect the recent federal uplisting of this DPS as endangered.
Draft documents are provided for informational purposes only. Drafts may contain factual inaccuracies and may not reflect current WDFW policy.