Olive Ridley Sea Turtles

Olive Ridley Sea Turtles (Lepidochelys olivacea)  by Alma Lopez

(Olive Ridley Project)

About

Olive Ridley turtles are often known as Pacific Ridley Sea turtles. Their name is linked to their olive green heart-shaped shell. They are considered the smallest, in size, of the turtle species. The average size of an adult turtle ranges from 2 to 2.5 feet in length and weighs about 80 to 100 pounds. The females lay an average of 100 to 110 eggs per bundle and usually nest 1 to 3 times per season. The Olive Ridley turtles are known for their arribada (meaning “arrival”) behavior. Arribada, or arribazone, is defined as the mass nesting process of the Olive Ridleys.

Geographic

The light orange is the Olive Ridley Sea Turtle Range
(National Geographic)

They are located in the tropical regions of the Atlantic, Pacific, and Indians Oceans and can mostly be found in the beaches of Mexico south of Colombia, eastern India and Sri Lanka; a small amount can also be found along the West coast of Africa. Although they don’t nest along U.S coast beaches, they sometimes use the southwestern coast water during feeding migration.

Populations Changes

The Olive Ridley Sea turtle is the most abundant sea turtle in the world and its population varies within various regions. Even though they are considered the most abundant, it wasn’t until recent years that they suffered from commercial exploitation reducing their population. In the eastern Pacific, at least 10 million Olive Ridleys inhabited the seas off of the coast of Mexico until more than 1 million of them were commercially harvested in 1968. This led to major decline in population for the Olive Ridleys.

Listing Dates and Types of listing

Dated listed: July 28, 1978

According to the Recovery Plan for the U.S. Pacific populations, the Olive Ridley turtles are classified as endangered along the coast of Mexico and threatened in the rest of the regions in the Pacific. 

Causes of Threats and listing
Egg poaching and over-harvesting of the Olive Ridleys in Mexico led to a decline of all but one of the largest turtle nesting populations in the area. An attempt to protect the Olive Ridley sea turtles, the government made egg poaching illegal in most countries in the eastern Pacific coast. However, egg poaching is still a threat as laws are hardly imposed and because egg poaching helps maintain a stable economy. The Olive Ridleys are exploited for food, bone meal, oil, leather, fertilizer, and bait. In the mid-1960s there was a major decline in their population when Mexico started a turtle leather trade with Europe (mainly Italy) and Japan; this was one of the largest over-harvest. Fifteen years following the decline, millions of turtles were victims until the establish trade industry was banned.

Olive Ridley caught in a fishing net (Grind Tv)

While Mexico is the primary location of the endangered  Olive Ridleys, the U.S. water is classified as the primary threat to the Olive Ridleys because they are incidentally taken by fisheries and boat collisions. There are a few incidents where the sea turtles would incidentally be captured and/or killed by U.S. tuna purses seine fishermen in the Eastern Tropical Pacific (ETP); this led to an annual mortality of less than 100 turtles.

Another challenge that these vertebrates face is the mystery of their arribadas. Females tend to travel a hundred to a thousand of miles to return to their birth beaches to nest. The danger of this is that biologists can’t predict when this event starts so the locations where they return are unpredictable in all the arribadas. This also creates a challenge for researchers and biologists because it difficult to see what type of environment these turtles need to reproduce.

Description of Recovery Plan

Date Issued: January 12, 1998
Name of Plan: Recovery Plan for US Pacific Population of the Olive Ridley Turtle (Lepidochelys olivacea)

Recovery Criteria: To consider delisting all of the following must be met:

1) All regional stocks that use U.S. waters have been identified to source beaches based on reasonable geographic parameters.

2) Foraging populations are statistically and significantly increasing at several key foraging grounds within each stock region.

3) All females estimated to nest annually (FENA) at "source beaches" are either stable or increasing for over 10 years.

4) A management plan based on maintaining sustained populations for turtles is in effect.

5) International agreements are in place to protect shared stocks.

Actions Needed: Three major actions are needed to achieve recovery:

1) Minimize incidental mortalities of turtles by commercial fishing operations.

2) Support the efforts of Mexico and the countries of Central America to census and protect nesting Olive Ridleys, their eggs and nesting beaches.

3) Identify stock home ranges using DNA analysis.

What can we do?

Even though there is a recovery plan in attempt to save these vertebrates, as of August 2007 they don’t have a final approved recovery plan. As we wait for the plan to be finalized there are some actions we can take to help reduced threats to the Olive Ridleys. The following are a few examples:

(World Wildlife Fund)

1. Adopt a Turtle: https://gifts.worldwildlife.org/gift-center/gifts/Species-Adoptions/Sea-Turtle.aspx?sc=AWY1302WC922&_ga=1.17213369.1046383166.1479755118

2. Volunteer/educational programs/Billion Baby Turtles: http://www.seeturtles.org/olive-ridley-turtles/

3. Reduce our consumption of sea food.

Other Resources

National Geographic: Over 100,000 Sea Turtles Nest at the Same Time|National Geographic https://youtu.be/tEd_g9RypHE

Ted-Ed|The Survival of the Sea Turtle: website: http://ed.ted.com/lessons/the-survival-of-the-sea-turtle Youtube: https://youtu.be/t-KmQ6pGxg4

World Wildlife Fund-Entangled Olive Ridley Turtle Cut free from Debris and Release: https://youtu.be/GfqtYq-lIt4

Work Cited

National Geographic. “Olive Ridley Sea Turtle” National Geographic. National Geographic, n.d. Web. 16 Nov. 2016 < http://animals.nationalgeographic.com/animals/reptiles/olive-ridley-sea-turtle/>

National Wildlife Federation. “Olive Ridley Sea Turtle” National Wildlife Federation. National Wildlife Federation. n.d. Web. 28 Nov. 2016. < http://www.nwf.org/wildlife/wildlife-library/amphibians-reptiles-and-fish/sea-turtles/olive-ridley-turtle.aspx>

Olive Ridley Project “Sea Turtles” Olive Ridley Project. Olive Ridley Project . n.d. Wed. 26 Nov 2016. <http://oliveridleyproject.org/sea-turtles/>

Strege, David. "Massive Olive Ridley Sea Turtle Deaths Reported off India." GrindTV.com. N.p., 26 Feb. 2014. Web. 26 Nov. 2016. <http://www.grindtv.com/wildlife/massive-olive-ridley-sea-turtle-deaths-reported-off-india/#01ye8W8649AsDjt4.97>

U.S Fish & Wildlife Services. “5-yr Review Plan”. U.S Fish & Wildlife Services Services Ecos. U.S Fish & Wildlife Services. 21 Aug 2007. Online PDF <http://ecos.fws.gov/docs/five_year_review/doc1077.pdf>

U.S Fish & Wildlife Services. “Olive Ridley Sea Turtle (Lepidochelys olivacea)” U.S Fish & Wildlife Services North Florida Ecological Services. U.S Fish & Wildlife Services. Jan 2015 .Web. 26 Nov. 2016. < https://www.fws.gov/northflorida/seaturtles/turtle%20factsheets/olive-ridley-sea-turtle.htm>

U.S Fish & Wildlife Services. “Recovery Plan for US Pacific Populations of the Olive Ridley” U.S Fish & Wildlife Services Ecos. U.S Fish & Wildlife Services. 12 Jan 1998. Online Pdf <http://ecos.fws.gov/docs/recovery_plan/981201a.pdf> 

World Wildlife Fund. “Olive Ridley Turtle”. World Wildlife Fund. World Wildlife Fund. n.d. Web 25 Nov. 2016.  < http://www.worldwildlife.org/species/olive-ridley-turtle>