Showing posts with label Eastern Pacific Green Sea Turtle. Show all posts
Showing posts with label Eastern Pacific Green Sea Turtle. Show all posts

Tuesday, March 6, 2018

Eastern Pacific Green Turtle by Sam Korff


The Eastern Pacific Green Turtle

Chelonia Mydas

By Sam Korff

The Endangered Green Sea Turtle
© 2018 (Animal Spot)
Description and Ecology
The green sea turtle (Chelonia mydas) is a widespread population of marine reptile initially described by Carl Linnaeus as Testudo mydas in 1758. More specifically, the East Pacific Green Turtle is a highly migratory subspecies concerned in areas such as Hawaii and along the west coast of North America where it can travel thousands of miles to breed and feed. It is different from the green sea turtle in both size, and shape, where it’s average size, is about 3 feet long weighs around 300 pounds. This makes the eastern Pacific green turtle smaller, weigh less, and have a narrower upper shell than other regions of green sea turtle. The diet and habits of green sea turtles change as they age; they lay eggs/are born on beaches, the young are carnivorous, but as they mature and move into deeper coastal waters they become omnivorous until eventually most adult sea turtle become strictly herbivorous.


Geographic and Population Changes
Eastern Pacific Green Turtle Migration
 Around Central America
© http://www.plosone.org
Defining the geographic range for sea turtles in the Pacific Ocean is a tough task due to the migratory nature of the species. The main geographic scope in this blog concerns the eastern Pacific Ocean: the west coast of the continental United States and Mexico; in the central Pacific, the state of Hawaii and the unincorporated U.S. territories in the east-central Pacific. The annual number of nesting females has declined by 48% to 67% over the last three generations. Excessive exploitation of the East Pacific green turtle throughout its range has caused a dramatic decline in numbers over the 1900s. This decline was definitely caused by the huge overharvest of turtles in the Sea of Cortez between 1950 and 1970, and the intense collection of eggs between 1960 and early 1980 on mainland beaches of Mexico.There are no known nesting areas on the US Pacific coast.


Listing Date and Type of Listing
Official Listing on ECOS
© https://ecos.fws.gov/
In recent decades the species has moved from unrestricted exploitation to global protection, yet intentional and unintentional means leave the wild populations of the species facing a high risk of extinction. The east pacific green turtle was listed in the U.S. Endangered Species Act (ESA) of 1973 as endangered across its’ range. All populations of chelonia mydas are classified as Endangered in the International Union for Conservation of Nature and Natural Resources' (IUCN) Red List and the Convention on International Trade in Endangered Species (CITES). The eastern Pacific, Hawaiian and Southern California sub populations are designated threatened.



Cause of listing and Main threats to its continued existence
Related image
Plastic pollution entangles turtles
and can be mistaken for food
© 2016 (Sergi Garcia)
From eggs to adults, green sea turtles are vulnerable to many threats including commercial harvest, incidental harm/bycatch, degradation of their habitat, pollution, and illegal trading. The population has exhibited a clear decline in numbers over the last 40 years and a more extreme decline in the last 30 years. Primary threats to the eastern green turtle subspecies in U.S. waters are from entanglement in debris and boat collisions. Primary threats in Mexico are the (illegal) harvest of turtles and eggs for leather and the exotic pet trade. Every year worldwide, hundreds of thousands of sea turtles are victims of bycatch caused by commercial fishing, where they are caught in shrimp trawl nets, longline hooks, and in fishing gillnets. Additionally, the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) prohibits the international trade in all sea turtle species and their parts, yet illegal trafficking persists.


Description of Recovery Plan
Green turtle being treated for a 6-inch
split in her shell caused by boat collision
© The Turtle Hospital
There is a total of 6 recovery plans for the green sea turtle, where the most recent recovery plan describes US Pacific and East Pacific regional populations. The Recovery Plan for U.S. Pacific Populations of the East Pacific Green Turtle was created in 1998, and outlines the major actions needed to achieve recovery. The primary action is to prevent incidental mortalities by commercial fishing operations, and boat collision, particularly within San Diego County, California. The next important action is political, to support the efforts of Mexico and the countries of Central America to census and protect nesting East Pacific green turtles, their eggs, and nesting beaches. The last actions are to determine important information on the population size and status in the U.S., the home ranges, and identification and protection of primary forging areas in the U.S.


What can you do?
It is very important that you continue the education of yourself and others about this topic in order to become activists for it, so you're already doing a great job! Also, it's very important to consider your own ecological footprint; particularly with plastics and other non-biodegradable resources that could potentially end up in our waterways. Political solutions will be the most practical solves to stopping the pollution and habitat degradation, but other more fun activities can involve Ecotourism based on sea turtles to help protect them.
Image result for save the turtle
© thelastplasticstraw.org


Want to learn more? Here are some additional resources!



References:
Seminoff, J.A. (Southwest Fisheries Science Center, U.S.). 2004.Chelonia mydas. The IUCN Red List of Threatened Species 2004: e.T4615A11037468. 



Recovery Plan (1998) - East Pacific Green Turtle - NOAA Fisheries. ecos.fws.gov/docs/recovery_plan/981201f.pdf.
Recovery Plan (1998) - Pacific Green Turtle - NOAA Fisheries. ecos.fws.gov/docs/recovery_plan/981201f.pdf.
“Recovery plan for U.S. Pacific populations of the East Pacific green turtle (Chelonia mydas) /.” 1998, doi:10.5962/bhl.title.62214.
“Sea Turtle.” WWF, World Wildlife Fund, www.worldwildlife.org/species/sea-turtle.
Service, U.S. Fish and Wildlife. Species Profile for Green sea turtle (Chelonia mydas), ecos.fws.gov/ecp0/profile/speciesProfile?spcode=C00S.

US Department of Commerce, NOAA, National Marine Fisheries Service. “Home page of NOAA Fisheries Service - Pacific Islands Regional Office.” Green Sea Turtle :: NOAA Fisheries Pacific Islands Regional Office, 21 June 2006, www.fpir.noaa.gov/PRD/prd_green_sea_turtle.html.
Amorocho, Diego F., et al. “Multiple Distant Origins for Green Sea Turtles Aggregating off Gorgona Island in the Colombian Eastern Pacific.” PLOS ONE, Public Library of Science, journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0031486.
Armstrong, Dave. “Endangered green turtle migration mapped.”The Earth Times, 22 Feb. 2012, www.earthtimes.org/nature/green-light-migrating-turtles/1806/.