Report of Chrysaora caliparea (Reynaud, 1830) Swarm from the Coastal Waters of Odisha, Western Bay of Bengal

A massive congregation of scyphozoan jellyfish Chrysaora caliparea (Reynaud, in: Lesson (ed) Centurie Zoologique, ou choix d'animaux rares, nouveaux ou imparfaitement connus, F.G. Levrault, Paris, 1830) was encountered along the coastal waters of Rushikulya and Gopalpur, east coast of India during the winter monsoon survey of 2021, adding a new swarm record to the Indian waters. This sudden drastic outburst of C. caliparea outlined thousands of live specimens, with the abundance ranging from 400 ± 70 ind./m³ to 550 ± 60 ind./m³ in Gopalpur and Rushikulya, respectively. On the contrary, the average abundance of phytoplankton and microzooplankton was on the downturn. The mean sea surface salinity (SSS), sea surface temperature (SST), and Chlorophyll-a concentration were 33.60 psu, 26.62 °C, 0.75 mg/m³, respectively, in Rushikulya and 33.44 psu, 26.48 °C, 0.57 mg/m³, respectively, in Gopalpur swarm stations. Dissolved oxygen (DO) was marked high in Gopalpur. Together, our study delineates the swarm-forming potential of Rushikulya and Gopalpur waters, pointing to the need for more research into how various factors can impede ecosystem balance in these vital Indian coastal areas.