UNIT 25 

 SEA TURTLES 



of beach in the State ot Tamaulipas on the Carib- 

 bean coast of Mexico. This single population un- 

 derwent a dramatic decline since 1947, when, on 

 a single day, 40,000 Kemp's ridleys were filmed 

 coming ashore to nest. The population pkmimeted 

 to fewer than 1,000 females nesting annually 

 through the early 1980's. Today, under strict pro- 

 tection, the population appears to be in the earli- 

 est stages of recovery (Figure 2S-1). The increase 

 can be attributed to rwo primary factors — tuU 

 protection of nesting turtles and their nests in 

 Mexico and the requirement to use turtle excluder 

 devices (TED's) in shrimp trawls both in the 

 United States and Mexico. 



The green turtle nesting population in the 

 southeastern United States appears to be stable. 

 Rased on genetic information, subpopulations 

 throughout the North and South Atlantic com- 

 mingle on the foraging grounds, but only one 

 population nests in the continental United 

 States — along Florida's east coast. Fhe annual 

 number of nests fluctuates greatly, usually alter- 

 nati[ig between high and low years. In recent years, 

 the number of nests deposited annually has ranged 

 from less than 430 to over 3,800. 



The leatherback is widely distributed in the 

 Atlantic Ocean, Gulf of Mexico, and Caribbean 

 Sea. In the United States, the largest nesting as- 

 semblages of leatherbacks are found in the U.S. 

 Virgin Islands, Puerto Rico, and Florida. Nesting 

 data for these locations have been collected since 

 the early 1980's and indicate that the annual num- 

 ber of nests is likely stable; however, information 

 regarding the status of the entire leatherback popu- 

 lation in the Atlantic is lacking. 



The hawksbill is most commonly found in the 

 Caribbean, but also regularly occurs in southern 

 Florida and southern Texas. Within the continen- 

 tal United States, a small amount of nesting oc- 

 curs in southern Florida. The largest nesting as- 

 semblages of hawksbills in the United States are 

 found at Mona Island, Puerto Rico; Buck Island, 

 U.S. Virgin Islands; and at other sites in the U.S. 

 Virgin Islands and Puerto Rico. There is clear and 

 convincing evidence that hawksbill populations in 

 the Atlantic have been greatly depleted during the 

 2()th century as a result of overharvest for trade in 

 products made from their shell. 



Number 

 of nests 



I 



I 



78 79 80 81 82 83 84 85 



87 88 

 Year 



Pacific Region 



In the Pacific, most reproductive colonies of 

 the olive ridley are in continental coastal areas and 

 rarely on oceanic islands. Although large nesting 

 assemblages of olive ridleys are found along the 

 Pacific Coast of Mexico and Central America, there 

 continues to be significant pressure on this popu- 

 lation from harvest of eggs and incidental capture 

 in trawl and longline fisheries. 



Major North Pacific nesting populations of the 

 loggerhead occurs in Japan and, in the South Pa- 

 cific, in Australia. At different stages of their life 

 cycle loggerheads occupy oceanic waters and 

 coastal benthic habitats around continents. In the 

 open ocean they are apt to be associated with con- 

 vergence zones, oceanic fronts, and boundary cur- 

 rents. Loggerheads have been recorded in waters 

 around the Northern Mariana Islands, American 

 Samoa, and Hawaii but are uncommon there. Fhe 

 status of loggerhead populations in most areas of 

 the Pacific is imknown due to a lack of historical 

 data on their distribution and abundance. How- 

 ever, long-term data on nesting and foraging popu- 

 lations in Queensland, Australia, indicate that log- 



92 93 94 95 96 97 



Figure 25-1 



Number of Kemp's ridley 

 nests observed annually at 

 Rancho Nuevo.Tepehuajes, 

 and Barra delTordo, Mexico, 

 1979-98 (Gladys Porter Zoo, 

 1997; R. Marquez M.', un 

 published data). 



'R. Marquez M., SEMARNAP/INP, CRIP-Manzanillo, Pro- 

 gram Nacional dcTortugas Marinas, P VentanasS/N. A.P s')l, 

 Manzanilln, C.iluiia. Mexico 28200 



263 



