World Status, Exploitation and Trade - WIDECAST

PHILIPPINESambiguous. Reyes ( in litt. . 23 September 1986) cites two sets of figuresfor the egg production on Taganak.; one gives the number of clutches pernight in August and September respectively as 8.37 and 6.18, and the other(shown in Table 159) as 4.9 and 3.7. Similarly, there is confusion over thenumber of nests on Baguan in 1984; at one point, the total numbers ofclutches produced in August and September were said to be 628 and 605respectively (Table 159), while elsewhere Reyes reported that only 384 nestswere laid on Baguan between 19 July 1984 and 4 September 1984, giving a meanof only eight nests per night. Numbers of nests per night on Taganak in theearly 1980s are only around 14-16% (depending on which set of 1984 figuresare used) of those in 1951; numbers on Baguan are 17-38% of those in 1951(depending on which of two sets of figures are used).On the other hand, the total annual egg production In the islands in 1984(Table 160) appears to have fallen only by 30% since 1951, but this isprobably misleading. The 1984 figures are based on nest counts, andrepresent the total numbers of eggs laid, whereas the figures for 1951 areextrapolated from the numbers of eggs harvested on only one island in onemonth. The numbers of nests per night (Table 159) probably give a betterestimate of the declines in turtle populations.Nesting season According to Domantay (1953), some nesting occursthroughout the year in the Turtle Islands, but most is May-September,usually with a peak: in August; while five females may nest nightly onTaganak. in January, 65 may nest nightly in August. Limpus (1985) quotedfigures which indicated that 45% of the nests on Baguan were laid inAugust-October. Most nesting in the Quiniluban group is November-March,during the north-east monsoon (which minimises human disturbance) (Matillanoand Ladra, 1986)Foraging sites Little information is available, but the Turtle Islandsare rich in suitable lagoons, coral reefs and beds of aquatic vegetation(reportedly algae, not seagrass) and good numbers of C. mydas appear toforage in the area (Domantay, 1953). It is not clear if there is a residentpopulation here, or if foraging turtles and nesting turtles in the area arefrom different populations. Similarly, the Quiniluban Islands provideextensive foraging grounds, with algae and seagrasses present; most C. mydasobserved here were immatures (Matillano and Ladra, 1986).Two of ten sub-adult C. mydas captured at sea over presumed foraging groundsin the Quiniluban group, tagged and released, have been recoveredsubsequently; they had grown some 20-27 cm in 16 months (Matillano andLadra, 1986).Migration Little information is available. Some tagged turtles havebeen shown to move between the Philippines and Sabah portions of the TurtleIslands group on subsequent nestings in one season. Several C. mydas taggedwhile nesting in the Sabah Turtle Islands have been recaptured in thePhilippines, mainly around the central group of islands (de Silva, 1986).Two females, first tagged on P. Taganak in the Philippines, were recoverednesting in the Turtle Islands N.P. , Sabah, Malaysia. One was tagged on9 September 1982 and nested on Bakkungan Kecil on 10 September 1982, theother was tagged on 9 October 1982 and nested on P. Selingaan on 17 November1982; both islands are around 29 km from Taganak.421