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In 1995, this Kemp's ridley was one of several kept in a small tank at the Cayman island Turtle Farm. At the time, it was possible that these Kemp's ridleys might soon have been the only ones surviving on the planet. In recent years, the population of Kemp's has slowly started to recover. 46K JPEG |
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The big threat to the kempi today is no longer the coyotes or egg hunters that brought about the original decline. The factor to reckon with now is incidental catch by shrimp trawlers. With the breeding population down to no more than twelve hundred mature females, each turtle caught by a net dragged for other species represents a significant loss. So despite the most powerful rescue effort that any sea turtle has ever received, Kemp's ridley is by all odds the most precariously ensconced marine turtle in the world.
Archie Carr
The Sea Turtle - So Excellent A Fishe
p. 241
1986, University of Texas Press
Some of the following is based on information from the Recovery Plan for U.S. Population of Kemp's Ridley Sea Turtle, U.S Fish and Wildlife Service and National Marine Fisheries Service, 1992. Obtained from the U.S. National Marine Fisheries Service, and used with their kind permission.
Kemp's Ridley (Lepiochelys kempii) has received protection in Mexico since the 1960s and was listed as endangered throughout its range in 1970 under United States law.
In 1963, using a film made in 1947 by the amateur cameraman Ing. Herrerra, Archie Carr and Henry Hildebrand estimated that on the day the film was made, 40,000 Kemp's ridley females nested on a single beach in northeastern Mexico. This arribada indicates that a much larger adult population existed.
The April 2001 Marine Turtle Newsletter carried a report that in 2000, slightly over 6,000 nests were counted. This is excellent news, since the estimated number of nests in 1985 was fewer than 200. The Kemp's is a long way from full recovery, however.
The Recovery Plan has this to say:
"The population crash that occurred between 1947 and the early 1970s may have been the result of both intensive annual harvest of the eggs and the mortality of juveniles and adults in trawl fisheries (Magnuson et al. 1990). The recovery of the species has been forestalled primarily by incidental mortality in commercial shrimping, preventing adequate recruitment into the breeding population."
Because the Kemp's ridley turtle at the time had only a single known nesting site (Rancho Nuevo, Mexico), inhabits a much restricted breeding range, and faces increasing threats from the human species, the Recovery Plan admits that a recovery might not be possible. The immediate goal of the Plan was to move the Kemp's ridley from the Endangered list to the Threatened list.
Today, there is better protection for the nesting beaches and Turtle Excluder Devices (TEDs) are mandatory on shrimp boats. The Kemp's population has responded favourably, with a slow but steady increase in annual nests counts. The recovery is by no means certain, but signs are encouraging.
Kemp's ridley and its cousin, the olive ridley, are the smallest known sea turtles. Adults generally weigh less than 45 kg. The straight carapace measures around 65 cm, and is nearly as wide.
The colour changes significantly as they mature. Hatchlings are grey-black top and bottom, while adults have a lighter grey-olive carapace and cream-white or yellowish plastron.
It is not clear that Kemp's ridleys have ever been hunted for their meat, although heavy exploitation of marine turtles around the turn of the century might well have included the Kemp's. Today, the Kemp's ridley faces two grim threats: loss of their nesting beaches, and death by drowning in shrimp trawls.
A major threat to the Kemp's ridley nesting beach is human encroachment. Parts of the nesting area are officially protected. In the past, enforcement was sometimes a problem, but protection has improved in recent years. The nesting sites are also vulnerable to the threats described in Threats To Marine Turtles. The Kemp's is particularly vulnerable to the loss of nesting habitat, since nearly all known nests of the Kemp's are concentrated on a single beach in Mexico.
The largest threat to the Kemp's ridley continues to be death by drowning in shrimp nets. Between 500 to 5,000 are killed in this way each year.
In 1987, the shrimping fleet around the Gulf of Mexico and south Atlantic caught an estimated 45,000 or more turtles, killing approximately 11,000. Some estimates run the numbers 3 to 4 times higher. Sea turtles wash up with alarming regularity on beaches where the trawling and gill netting activity is high.
A simple device called a TED has existed for many years and has been proven effective in reducing the number of drownings. TEDs are designed to keep objects larger than a shrimp out of the net. Debris, turtles, and other bycatch escape from the net without adversely affecting the shrimp catch.
In the U.S., both federal and state governments have spent considerable time and money to promote the use of TEDs, hoping that shrimpers would use the devices voluntarily. Unfortunately, there was strong opposition from the shrimping industry. In 1989, U.S. federal regulations required the use of TED's by shrimp trawlers operating in U.S. waters. Compliance remains a problem, but since the TED regulations were implemented, the Kemp's has begun a slow recovery.
The Sea Turtle Restoration Project has been organizing support for a marine preserve along the Texas coast to protect the Kemp's ridley. You can learn more about this campaign by visiting their website at www.seaturtles.org.
The two primary feeding grounds for adult Kemp's are both near major areas of oil exploration and production. The nesting beach at Rancho Nuevo was the victim of an oil spill in 1979 and continues to be vulnerable.
Kemp's ridley are also vulnerable to the pollution threats common to all marine turtles, as described in Threats to Marine Turtles.
The Kemp's Ridley is the most endangered of all marine turtles. Only 580 females nested in 1994, compared to 40,000 on a single day in 1947.
"They killed turtles, distributed the meat in the interior, dried calipee for sale, and mined the eggs in masses. Three years ago I realized that I had heard no definite report of an arribada since some time in the latter part of the 1950s. Now I have just finished canvassing every possible source of information, and it adds up to the dismal certainty that no arribada has been seen for at least seven years. Two or three skipped years might be atrtibuted to chance, because ninety miles is a long beach and there are not really many people there. Now, however, there is no escaping the snowballed evidence that the great arrivals have failed. Cotorras still straggle ashore along the Tamaulipas coast, but they are few and scattered. The fabulous conclaves of former years have gone the way of a thousand other sea turtle colonies before them."
Archie Carr
The Sea Turtle - So Excellent A Fishe
p. 157
1986, University of Texas Press
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