Scyphozoan jellyfish diversity and distribution along the north-eastern Arabian Sea, off Gujarat coast, India

Abstract

Swarming of Scyphomedusae in large numbers in the Indian Ocean and specifically in the north-eastern Arabian Sea has been found to impact fishing operations; however, information on the diversity and distribution of these enigmatic jellyfishes are scanty. Hence, a study was carried out along the Gujarat coast, India during 2017-2020. Field surveys were conducted to identify the areas where jellyfish landings or swarming were regularly reported and locations viz. Jakhau, Okha, Porbandar, Veraval and Navabandar emerged as jellyfish focal stations. Fisher-assisted onboard surveys were conducted from the jellyfish focal stations. The results revealed the occurrence of six Scyphozoan jellyfish species viz., Catostylus cf perezi, Rhopilema hispidum, Cassiopea cf. andromeda, Cyanea cf. nozakii, Chrysaora cf. chinensis, and Chrysaora cf. caliparea identified based on the morphological characteristics. This study also mapped the diversity of these jellyfishes to understand the species-specific occurrences along the Gujarat coast, India which would form a baseline for further monitoring of potential changes in the swarming of jellyfishes.

Keywords: Gujarat coast, Jellyfish, North-eastern Arabian Sea, Scyphomedusae