World Status, Exploitation and Trade - WIDECAST

ECUADORHurtado notes some movement between nesting beaches: 9.8% of turtlesobserved more than once at nesting beaches during a season appeared at morethan one beach while 12.5% of remigrating turtles were recorded at differentbeaches in subsequent seasons. Of the latter (n = 12), six involvedmovements between islands (treating Santa Cruz and Baltra as one island)(Hurtado, 1984). This total may be artificially elevated as it includesindividuals which visited nesting beaches but did not nest (Hurtado, 1984).Trends in nesting numbers No data are available to assess long-termtrends. Data from post-1974 studies indicate considerable short termfluctuations in nesting numbers (see Table 57). These were similar on eachof the beaches under study and appeared to be directly related tooceanographic conditions, with highest numbers in years when the Equatorialfront was well-developed and marine productivity high (1978, 1982) andlowest in El Nino years (1975, 1976, 1983) (Hurtado, 1984).Nesting season Laying starts around early December and lasts until theend of June with a peak, in late February/March (Green, 1984b).Foraging sites Green and Ortiz-Crespo (1981) note that the mostimportant feeding grounds in Galapagos appear to be the beds of algae aroundthe western islands of Isabela and Fernandina. There were indications thatsome individuals, particularly immatures and virgin females, tagged on thefeeding grounds were present all year round and some females tagged on thenesting beaches were recaptured on the feeding grounds well outside thenesting season, implying that they too may have been year round residents inGalapagos. However the long-range recoveries (see below) from off theCentral and South American Pacific mainland imply that at least part of thepopulation is migratory.Migration Green (1984a) discusses long-distance movements of GalipagosGreen Turtles. Out of 5844 turtles tagged between 1970 and 1979, a total of23 have been recovered away from the islands, along the Pacific coastline ofSouth and Central America. This indicates that a proportion of thepopulation, at least, migrates away from Galipagos, although the recoveryrate is lower than for Green Turtles studied elsewhere. Of the total, tenwere from Peru, five from Ecuador, one from Colombia, four from Panama andthree from Costa Rica. Twenty of the recoveries were females and threemales. One female was marked at Quinta Playa, recaptured off the coast ofmainland Ecuador and subsequently recorded nesting again on Quinta Playa,one of the very few instances of two-way migration recorded anywhere (Green,1983).POPULATION : Eretroochelys imbricataEretmoqhelys is encountered occasionally in Galapagos but has never beenshown to nest (Green and Ortiz-Crespo, 1981). Sightings have been madearound the following islands: Fernandina, Isabela, Pinzon, Santiago, SantaCruz, Baltra, Santa Fe , San Cristobal, and Floreana (Green and Ortiz-Crespo,1981) .THREATSThe population on Galapagos appears to be relatively secure at present.Apart from a small amount of exploitation (see below), threats identifiedinclude nest-predation by feral pigs and by the scarabeid beetle Trox173