Fatty acid biomarkers to indicate the organic food sources of mudskipper species boleophthalmus boddarti and periophthalmus gracilis in Setiu wetlands, Terengganu

Abstract

Fatty acid compositions m the tissue and feces of two mudskipper species; Periophthalmus gracilis and Boleophthalmus boddarti, and sediment samples from Pengkalan Gelap (Periophthalmus gracilis) and Kampung Fikri (Boleophthalmus boddarti) which were collected in August and October 2007 from the mangrove area of Setiu Wetlands were identified, in order to assess the diet of these two mudskippers. Both species contain a total of 45 identifiable fatty acid methyl esters in their tissues, feces and sediments where they were collected from. Total lipid concentration was highest in the tissue of Periophthalmus gracilis when compared to the Boleophthalmus boddarti. There were a total of five components of lipid that has been found in all samples which are phospholipids, sterols, triglycerols, fatty acid and waxes. Fatty acid dominated the lipid components in all samples, except for the sediment samples in Pengkalan Gelap and Kampung Fikri in August. Overall, the tissue of Periophthalmus gracilis showed the highest concentrations of PUF As, and the tissue of Boleophthalmus boddarti showed the highest concentrations of MUF As. There were six food sources that can be identified in the diets of mudskipper species Periophthalmus gracilis and Boleophthalmus boddarti, namely bacteria, dinoflagellates, green macroalgae, mangrove detritus, diatoms, and copepods. Bacteria were the major food sources that have been consumed by these two mudskipper species in this study. The diet pattern of these mudskippers did not differ significantly between August and October 2007 (p>0.05).