World Status, Exploitation and Trade - WIDECAST

MALAYSIAMALAYSIA:SABAHPOPULATIOK :Chelonia mydasNesting sites The principal nesting beaches are on Pulau Gulisaan,P. Selingaan and P. Bakkungan Kecil, constituting the Turtle IslandsNational Park, in the Sulu Sea some 30 km north of Sandakan. Sparse nesting(not always confirmed to be by C. mydas ) has been recorded at around 30other sites, mostly on small islands (de Silva, 1969a). Tegapil andLankayan in the north, and Sipadan (off Semporna) appear to be the mostproductive (data of Harrisson 1961-1964, in Polunin, 1975). The TurtleIslands N.P. lies entirely within Sabah territory; other islands in thegroup extend into Philippines territory (where turtles also nest).Nesting numbers No quantitative surveys of nesting females have beencarried out. Egg yield data (Table 116), however, can be used as a veryapproximate index of nesting numbers, given the assumption that most eggslaid are harvested; according to de Silva (1982) "practically every egg" onthe turtle island beaches is harvested during dense nesting periods. Theislands were privately owned until the end of 1972, during which time theright to collect all eggs for sale was leased out, and became the core ofTurtle Islands N.P. in 1973, since when most eggs have been used forhatchery purposes. A count of C. mydas nests is available for 1982-1986; inthese five years E. imbricata nests were on average 13.4% of the total nestscounted, so all total egg yield figures before 1982 might be expected toinclude a similar proportion of E. imbricata nests (but the figures belowhave not been so adjusted). The mean annual number of C. mydas nests in1982-1986 was 2633. The mean number of C. mydas tagged over the same periodwas 1375, giving an average of 1.9 nests per turtle tagged. Marsh( in litt. , 18 September 1986) reported that between two and six C. mydasnested nightly in September on P. Sipadan. More sporadic nesting onP. Sipadan was reported by de Silva ( in litt. . 26 August 1988) and hepointed out that all eggs laid on the island were collected by locals underthe terms of their "native rights". According to Harrisson (1964, cited inPolunin, 1975) some 110 000 eggs (probably mostly C. mydas ) were probablycollected in other islands in north and south-east Sabah in 1961-1964;assuming this is an annual average, an additional 350 females might havebeen nesting in Sabah outside the Turtle Islands.Trends in nesting numbers While the egg yield data need to beinterpreted with great caution, they do suggest that a moderately steadydecline in nesting effort, of around 45%, has occurred over the past twodecades, most evident from the mid-1970s onward. The 1986 egg harvest was51% of the 1965 harvest and only 34% of the 1947 harvest, but it is notclear how reliable the yield record for the latter year is. Those closelyfamiliar with the situation in the field have stressed that turtlepopulations had declined significantly over this period and were severelythreatened (de Silva, 1982; in litt. , 3 September 1986).Nesting season Nesting occurs on the three turtle islands virtuallythroughout the year, but most takes place in August-October, with a peak inSeptember (de Silva, 1969a, 1969b).Foraging sites Although the species may occur widely in Sabah waters, noinformation on favoured feeding grounds is available. C. mydas have beenrecorded around the Semporna group of islands, off Sabah 's east coast (Wood,307