STABLE ISOTOPES (δ13C AND δ15N) ANALYSIS INDICATE RESOURCE PARTITIONING BY ELASMOBRANCHS FROM THE TROPICAL COASTAL WATERS OF KUALA PAHANG, MALAYSIA

Abstract

Nearshore habitats support high levels of biodiversity and important ecological processes such as trophic dynamics. This study aims to determine the trophic dynamics of elasmobranchs and other marine species from the coastal waters of Kuala Pahang, using stable isotope analysis. Samples of invertebrates, teleosts, and juvenile elasmobranchs were collected at the coastal waters of Kuala Pahang, and the composition of stable isotopes δ13C and δ15N were determined. Of all species, teleosts had the narrowest range of δ13C values, of between -17.5‰ and -16.7‰, indicating their reliance on similar types of food resources. On the contrary, elasmobranchs had the widest range of food sources as indicated by the δ13C values, of between -26.8‰ and-16.8‰. The banded sicklefish (Drepane longimana) occupied the highest trophic level as indicated by a δ15N value of 12.4‰, whereas the red stingray (Hemitrygon akajei) had the lowest trophic level with a δ15N value of 4.9‰. The depleted δ13C values indicated resource partitioning among elasmobranchs, presumably due to the utilisation on estuarine-based carbon resources. This study highlights the potential importance of the estuary of Kuala Pahang as a feeding ground for juvenile elasmobranchs