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Are Leatherbacks Doomed to Extinction?

By Frank V. Paladino

Costa Rican Sea Turtles PI

††† Since the early 1980's my colleague Dr. James R. Spotila and I have led teams of researchers,students, and volunteers to Costa Rica to study leatherback and green sea turtles. We were fortunate to get to know Sr. Mario A. Boza who has served in various positions in the Costa Rican Ministry of the Environment†(MINAE) including

as Vice Minister, and in numerous Conservation NGO positions. Sr. Boza is fondly referred to in Costa Rica as the father of the National Parks system and was a driving force urging us to work in Costa Rica and help conserve sea turtles. The National parks in Costa Rica are one of the leading ecotourist destinations in the world and are renowned for their diversity, beauty and strong management by MINAE. We have Provided the data to MINAE needed to develop a new National Park "Parque Marino Las Baulas" to help protect leatherback sea turtles along the Pacific coast in the Guanacaste Provence on Playa Grande (photo #1). Over the past eight years we have had over 300 Earthwatch volunteers, 20 graduate students and numerous undergraduates from the USA and Costa Rica work with us on the scientific and conservation projects that have resulted in over 30 publications† in scientific journals. As a matter of fact one Costa Rican student Sr. Rodney Pietra Chacon, who did his graduate research working with us and his Costa Rican Professors from the National University of Costa Rica on Playa Langosta, is now the Park Director.

To see a brief National Geographic video on this project, click here.

†† Sadly over the past 11 years we have watched the rapid decline of the leatherbacks from a population that was about 1,350 female nesters per season to about 130 - 140 individual turtles who have nested there the past three years.† For a more detailed data go to our web page at decline is the result of over 15 years of almost complete harvest of the eggs laid by returning females and the loss of many nesting beaches to development for hotels, resorts, and private homes (see Figure 1 and photo # 2 of poacher on horseback). We have also observed a greater than 40% mortality in the returning adult female population over the last eight years. To be sure that these female who have not returned are† not just nesting elsewhere, we have conducted aerial surveys and checked beaches all along the Costa Rican coastline and found that there are few beaches left where the leatherbacks still nest. The situation is the same all along the Central American coastline from Mexico to Panama. At a recent meeting in January 1999 I spoke with Ms Laura Sarti, a Mexican leatherback researcher, who relayed to me some really depressing news. She reported that on the Pacific beaches of Mexiquillo where there were approximately 1,000† female leatherbacks nesting per year ten years ago now there was only one female who came ashore to lay only two nests. Leatherback turtles and others are also caught on long line fishery hooks. We, using satellite telemetry, followed the

†migrations of leatherbacks from the beaches in Parque Marino Las Baulas into the Central Pacific. Our findings published in the journal Nature (Morreale et al. 1996, Volume 384:319-320) indicated that leatherbacks migrated along a narrow corridor about 100 km wide away from the coast and out into the Pacific (Figure of migration). We, along with another research team who was working with the Mexican, Mexiquillo beach leatherback turtles, found that many of these satellite tagged turtles seemed to hit a zone in the Pacific as they migrated away from the nesting beaches where the transmitters and the turtles seemed to disappear. Both our research team and theirs (see Eckert 1997 Marine Turtle Newsletter 78:2-7) suspect that these turtles are being caught on long line and gill net fisheries found in these waters near the Galapagos and Easter Islands and off the coasts of Equador and Chile. Our 1996 research article in Chelonian Conservation and Biology (Spotila et. al. 1996 Volume 2(2):209-222) describes the declines of leatherbacks especially in the Eastern Pacific Ocean. We are very concerned that the population model we presented in this paper which describes the effects of fishing pressure, adult mortality, and loss of eggs due to harvest, on the survival of sea turtle populations is being ignored.


†††† Recent rulings in October 1998 by the World Trade Organization (WTO) have been of great concern to marine conservationists. The WTO has ruled that the 1989 Turtle Excluder Devise (TED) Law could not be enforced on the fleets of foreign importers of shrimp. The TED law that was passed by the US Congress and finally signed a few minutes before George Bush left the presidency was designed to protect many marine species, especially sea turtles, from needlessly drowning as a bycatch in the shrimp nets in USA waters. It also required any importer of shrimp to the USA to also comply with these fishing† practices so†

that US shrimp fishermen would not be undercut by cheap shrimp caught without the use of these TED devices. The TED (Figure of TED) is simply a gate in the net that allows for large marine species to escape from inside the nets. If these turtles, marlin, tuna, and other large marine species are dragged in the nets without these escape routes they are caught along with the shrimp and damaged or drowned in the nets and just dumped overboard. The foreign importers of shrimp argued that the USA TED law was forcing foreign fleets to comply with USA laws and† restricted free trade. The WTO ruled in October 1998 that this US TED law was an infringement on free trade and see the Earth Island web page at to check out the full details of this ruling and the arguments made concerning this case. The bottom line is that sea turtles will be needlessly killed because of the US appetite for shrimp. Shrimp fishing is one of the most inefficient fisheries with 10 - 30 lbs of so-called bycatch that must be dumped dead overboard for every 1 pound of shrimp caught. These shrimp fishing practices along with the long line fisheries especially off the Pacific Coast of Central America seem to have†

had a dramatic effect on the populations and migrations of sea turtles. It was estimated that over 20,000 turtles per year were killed and it may have been the leading cause for the demise of the Kempís Ridley sea turtle in the Gulf of Mexico. Kempís Ridley turtles were know to have nested on South Padre Island but were extinct from those beaches by the 1950's. There remains now only one beach "Rancho Nuevo" in Mexico where this most endangered sea turtle is found to nest in arribadas that historically had thousands of turtles emerging and nesting in these social aggregations in one - three nights a month but now these arribadas number only in the hundreds.

††† The combined effect of the nesting beach habitat loss, indiscriminate harvesting of eggs, the shrimp fishery, the long line and gill net fisheries has been the rapid decline of many sea turtles, billfish and other large marine species along the Central American coast. The ruling by the WTO and the reluctance of many countries to sign the International Sea Turtle Conservation Convention that is designed to protect these animals has led to the current sorry state of affairs. I believe that these rulings and the lack of concern will lead to the extinction of leatherbacks, at least in the Eastern Pacific, unless something is done to change the patterns we now see. We have worked hard to create new National Parks like Parque Marino Las Baulas to protect and maintain the nesting beaches but now the animals are being indiscriminately killed in the ocean by our fishing practices. We need to not only protect the beaches but the adults in the ocean as the grow and return to nest.

††† As a personal crusade I have decided to not eat shrimp unless I am sure they were obtained by a fleet using TEDís. In addition I have written to all the seafood chains and fresh/frozen seafood processors in the USA and pleaded that they continue to purchase only "Turtle Safe Shrimp" from fleets that comply with the USA TED laws. I hope that any of the many volunteers who have visited the many sea turtle projects sponsored by Earthwatch will rise up and also write to these companies, their congress representatives and whomever will listen to please save our oceans and these wonderful and fascinating animals. If you would like you can send your messages and letters to me at the following postal and e-mail addresses and I will forward them along to the companies and governmental agencies:

Mailing Address:

Department of Biology

Indiana - Purdue University

Fort Wayne, IN 46805-1499 USA