World Status, Exploitation and Trade - WIDECAST

ECUADORNesting numbers Green (1983) estimated that possibly 1200-3500 femalesnested annually in the archipelago, but noted that, in the absence ofintensive surveys during the nesting season of the majority of beaches used(see above), such estimates were approximate at best. Data have beencollected in the period 1976-82 for the major nesting beaches as follows:initial studies were concentrated on Quinta Playa (Isla Isabela) and LasSalinas (Isla Baltra) ; from 1979 the study was extended to: Bahia Barahona(Isla Isabela), Las Bachas (Isla Sta. Cruz) and Espumilla (Isla Santiago).In addition data were collected from Bartolome (Isla Bartolome) and laPicona (Isla Floreana) for one season each and sporadic observations weremade in Bahia Borrero and Caleta Negra (Isla Sta. Cruz) and Playa Sardina(Isla San Cristobal). Results are given in Table 57.Table 57. C. mydas nesting on principal beaches in Galipagos 1975-83.Source: Hurtado (198A). * = Incomplete data. ** = Data excluded fromcalculations of % on each beach.Nesting beach 1975 1976 1977 1978 1979 1980 1981 1982 1983 mean %total(Island)Quinta Playa 39* 315 308 610 300 A95 699 236* 37* 455 28.83(Isabela)Bahia Barahona181 120 288 288* 766 10* 339 21.48(Isabela)Las Salinas 48* 163 218 296 163 252 379 410 42* 269 17.05(Baltra)Las Bachas115 243 50* 330 229 14.51(Santa Cruz)Espumilla85 123 223 114* 144 9.13(Santiago)Bartolome15* 4444* 2.79(Bartolom^)La Picona(Floreana)9898* 6.21Playa Sardinaf**(San Cristobal)Playas Caleta Negra7**(Santa Cruz)Playa Bahia Borrero3**50.331.6Data in Table 57 indicate the number of individuals marked in each season,and thus the minimum number visiting nesting beaches in that season. Mostimportant beaches were those on Isabela which accounted for 50.3% of nestingindividuals and those on northern Santa Cruz (Las Bachas) and adjacentsouthern Baltra (Las Salinas) which accounted for a further 31.6%.Studies in the period 1980-82 indicate a mean of 0.86 nests per female perseason which is low compared with comparable figures for other well-studiedpopulations (e.g. Hawaii and Tortuguero, Costa Rica); 37% mounted thenesting beach but did not nest, 45% nested once and the remainder nested 3-5times. Observed remigration rate for the whole period (1975-83) was low(1.1%, or 88 of the total number of females marked during the study). Meanannual production of emerging nestlings has been calculated at c. 55 000(Hurtado, 1984).172