The student will learn about the endangered status of the Kemp's ridley sea turtle. Since all seven species of sea turtles are endangered, threatened or vulnerable, this lesson will acquaint the student with hazards to all sea turtle species, as well as with specific efforts to save the Kemp's ridley. The student will be given enough information to take an active role in this species' preservation through contacting appropriate government officials by letter writing, drawing a picture or by e-mailing.
Reportedly, Columbus' sailors had to use poles to push swarms of sea turtles out of the way of his three boats as they sailed through the Gulf of Mexico. Today, the Kemp's ridley sea turtle (Lepidochelys kempii) is the most endangered sea turtle in the world. Less than 60 years ago, the Kemp's ridley sea turtle was still abundant, with more than 40,000 turtles recorded nesting in a single day at the major nesting site in Mexico. Today, fewer than 3,000 Kemp's ridley nests are found in an entire year.
The Kemp's ridley spends it life in shallow waters of the Gulf of Mexico and along the east coast of the United States where it searches for crabs, its favorite food. Most Kemp's ridley turtles begin their lives when they hatch from eggs laid in northeastern Mexico in the state of Tamaulipas on a beach called Rancho Nuevo. A second nesting beach occurs in Padre Island, Texas. The female turtle lays approximately 100 eggs per nest and lay two or three nests a year between April and July. Six to eight weeks later, the eggs hatch. The baby turtles (called hatchlings) scurry to the Gulf of Mexico to begin their lives in the sea.
There are two main reasons for the decline of the Kemp's ridley sea turtle, one of the most endangered animals in the world: 1) the historical overharvesting of turtle eggs by people for food and sale (now virtually illuminated), and (2) the turtles' incidental drowning in shrimp nets.
The Mexican government began protecting the beach at Rancho Nuevo in the 1960s, and the harvesting of eggs of this species was effectively stopped. Despite this fact, the number of nests laid continued to decline until the mid 1980s when it stabilized and a slight increase has been noted in the years since 1994.
Shrimp has become a popular food in the developed world. American shrimp consumption has risen steadily in recent years. Our appetite for shrimp is satisfied by a world shrimp fishery in whose trawl nets an estimated 155,000 sea turtles drown yearly. In the Gulf of Mexico and Atlantic Ocean, many of those drowned sea turtles are Kemp's ridleys. The National Academy of Sciences has recognized shrimp fishing as the largest human-caused mortality factor for sea turtles in US waters, greater than all other human-caused factors combined.
Sea turtles, like most other marine wildlife, are also impacted by marine pollution (including plastic balloons and bags, which are mistaken for food), pollution from oil drilling and transport, destruction of coastal habitat for development, boat collisions, and incidental capture by various fishing activities.
On their nesting beaches, the outdoor lights that come with shoreline highways and resort hotels can fatally confuse sea turtle hatchlings, whose first motion across the sand is towards the brightest light, formerly the moon glinting on the water (see activity).
Scientists, conservationists, and governments have worked for many years to bring sea turtles back from the verge of extinction. Three major conservation activities have provided some relief:
1. Nesting beach protection. Since 1966, the Mexican government has protected the primary Kemp's ridley nesting beach at Rancho Nuevo in the state of Tamaulipas. Collection of turtle eggs is no longer allowed. Each year during the nesting season, Mexican and U.S. biologists work at the nesting beach counting turtles and moving eggs into 'corrals' where they can be protected from predation and poaching.
2. Headstarting. In an effort to create a second important nesting site for this species, the Mexican and U.S. governments worked together from 1978 to 1988. Each year they took approximately 2000 eggs from Rancho Nuevo in an experiment to see if the Kemp's ridley sea turtles could be 'imprinted' to the Padre Island, Texas beach. The eggs were hatched in Padre Island sand and the hatchlings allowed to run down the beach, allowing them to possibly 'imprint' a memory of the beach to which scientists hoped they might return to nest. Some were released then, others were caught to be reared in captivity for several more months. These 'headstarted' sea turtles were larger than new hatchlings, and, scientists hoped, had a better chance of surviving (less than 1 in 1,000- hatchlings are believed to survive to adulthood). After ten years this taxpayer funded project was discontinued, although Kemp's ridley sea turtles probably do not reach sexual maturity for 15-20 years. In the last few years, some of the nests that have been found at Padre Island have been traced to these 'imprinted,' headstarted sea turtles. A small but growing number of Kemp's ridleys are now nesting at Padre Island, Texas (thirteen nests in 1999).
3. Ocean Protection. Two different types of ocean protection activities have been used. The first is the creation of marine reserves around nesting beaches the other is the use of turtle excluder devices..
a. Marine Reserves: The Mexican government created a "no fishing" area in the waters off the main nesting beach at Rancho Nuevo to protect adult turtles from being incidentally captured in shrimp nets and other fishing gear. Conservationists are now trying to convince government officials to do the same thing around the new nesting beach at Padre Island, Texas.
b. Turtle Excluder Devices (TEDs) in shrimp nets: Sea turtles sometimes get swept into shrimp trawl nets and drowned. After many years of lobbying from conservationists, the U. S. and Mexican governments passed laws requiring all shrimp nets to be equipped with TEDs. TEDs or turtle excluder devices, also called trawler efficiency devices, are metal grids (like oval barbecue grills in appearance) sewn into shrimp trawl nets that allow turtles and other large marine animals to escape. Even with the mandatory requirement to use TEDs, many turtles continue to wash up drowned on Texas beaches during their nesting season. Some conservationists and scientists believe that some shrimp fishermen purposefully disable their TEDs, in the mistaken belief that TEDs reduce their shrimp catch. Some also believe that TEDs may not always be effective, especially if turtles are caught many times in a short period and do not have enough time to recover between captures.
Turtle Excluder Device (TED)
Shrimp trawl net
pen, paper, envelope and postage (unless e-mailing) is needed, in addition to the following addresses:
Governor Rick Perry
State Capitol Room S2.1
Austin, TX 78701
E-mail President Bush: email@example.com
Write a letter or draw a picture and/or send an e-mail message to Texas Governor Rick Perry and President George W. Bush and ask for the creation of a Marine Reserve in the waters surrounding Padre Island, Texas.
This activity also can be used to teach students how to properly write a business-style letter and address an envelope.
Enter the Sea Turtle Restoration Project Marine Reserve Art ContestÖ go to www.seaturtles.org/art.contest.cfm
Read The Great Ridley Rescue by Pamela Phillips published by Mountain Press Publishing Company. ISBN O-87842-229-3. (Limited number for sale from HEART for $15 plus $2.90 postage, P.O. Box 681231, Houston, Texas, 77268)
Use the WEB to find out what part school children played in Operation HEART (Help Endangered Animals-Ridley Turtles).