Genetic Diversity of Small Giant Clam Tridacna maxima in Kur Island, Biak Island And Manado and their Implications to Conservation

Giant clams are ecologically important bivalves in coral reefs. These marine organisms have been under anthropogenic pressures in almost all part of Indonesia. Even though this species is protected under Government Regulation (PP) No. 7, 1999, but the illegal harvesting is still happened. This not only caused the declining the number of individual and species, but also could lead to a decrease the genetic diversity of this species. Therefore, it is necessary to conduct research on the genetic diversity of Tridacna maxima based on COI genetic markers from Kur Island, Biak Island and Manado. The study used 15 samples T. maxima from Kur Islan (This study) then compared with genbank data (11 samples from Biak and 8 samples from Manado). Sequence analysis of mitochondrial (mt) DNA T. maxima resulted 432 base pairs, which contained 23 haplotypes with total numbers of 59 polymorphic sites. The results show that genetic diversity of the T. maxima population was very high (0.95). The genetic distance between populations in this study ranged from the lowest (0,009) for Kur vs Manado to the highest (0,043) for Biak vs Manado. The filogenetic tree showed that there were two main clades, i.e. 1) T. maxima calde of Kur, Biak, and Manado and 2) T. maxima clade of Biak. The pairwise method analysis (FST) showed a significant genetic structure in the population of T. maxima in Kur with Biak (Fst = 0.558; p = 0.000) and Manado with Biak (Fst = 0.427; p = 0.012), whereas there was relatively no significant differentiation within population in Kur and Manado (Fst = 0.087; p = 0.064). The conservation effort for T. maxima population in Kur island is prioritized by implementing the local wisdom called Sasi with strengthened by the formation of regional marine conservation area on research sites.