Feeding habits and trophic level of sharpnose stingray, Himantura gerrardi (Elasmobranchii Dasyatidae) in northern Oman Sea: effects of sex and size class

Document Type: Research Paper

Authors

1 Department of Marine Biology, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran

2 Department of Marine Biology, Tehran Science and Research Branch, Islamic Azad University, Tehran, Iran.

3 Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research Education and Extension Organization (AREEO), P.O. Box: 14965/149. Tehran, Iran.

4 Persian Gulf and Oman Sea Ecological Center, Iranian Fisheries Science Research Institute (IFSRI), Agricultural Research Education and Extension Organization (AREEO), Bandar Abbas, Iran.

Abstract

The feeding habits and trophic level of Himantura gerrardi were studied according to sex and size classes utilizing 80 individuals obtained using bottom trawl between May and December 2014 from Oman Sea. Collected specimens were divided in three size classes (small 58 cm) based on disk width (DW). Preys were identified in seven main zoological categories, where crustacean and polychaetes were the dominant in diets, which indicating this species is a demersal dwelling species. No significant differences were observed between sexes, but size classes showed a significance differences in their diets. Also, results showed a decreasing of feeding overlap between size classes by increasing of DW, suggesting that intraspecific competition reduced, which allows the coexistence of different size classes. Trophic level was positively correlated with the DW, which were lower than 4.0 for both sexes and different size classes, placing it in intermediate trophic level.

Keywords