| Abstract |
Aside from having an important ecological role in the ocean food web, small pelagic fishes have become the major food source in the Sulu-Celebes Sea (SCS) which is bordered by Indonesia, Malaysia and the Philippines. Conservation and management of these fishes are of prime importance because the people living around the SCS are highly dependent on these resources. Nevertheless, basic biological information, especially relating to genetic diversity, population genetic structure, and demographic patterns, are often deficient. In this study, population genetic methods were used to investigate the genetic structure and diversity as well as historical demography of four ecologically and economically important small pelagic fishes in the SCS: Auxis thazard (Lacep脙篓de, 1800); Bali sardine, Sardinella lemuru (Bleeker, 1853); Indian mackerel, Rastrelliger kanagurta (Cuvier, 1816); and bigeye scad, Selar crumenophthalmus (Bloch, 1793). Fish samples were collected from 5 geographic locations: (Philippines: Zamboanga, Tawi-Tawi and Palawan; Indonesia: Manado; and Malaysia: Kudat) around the SCS and muscle tissues were sequenced for the mitochondrial DNA (D-loop) control region (n = 150, 231, 169 and 224 for AT, SL, RK, and SC, respectively). Low overall FST values, high haplotype diversity but low genetic differentiation among haplotypes, and highly mixed clusters from BAPS analysis indicate no distinct genetic population structuring among the samples. Furthermore, neutrality tests, mismatch analysis and Bayesian skyline plots suggest population expansion for all species. Generally, these results indicate that the four marine pelagic species are very resilient over evolutionary time scales; yet, proper management is very necessary, especially because overexploitation of small pelagic fishes has already been reported in the SCS region. |
Mindanao State
University - Iligan Institute of Technology