01-05 December 2025
INCOIS, Hyderabad, India.
| Abstract Submission No. | ABS-06-0231 |
| Title of Abstract | Jellyfish diversity and niche partitioning during a scyphozoan swarm in the coastal Bay of Bengal: interactions and environmental drivers of coexistence |
| Authors | Alfisa Siddique*, Naveen Sagar Garbhapu, V.V.S.S. Sarma |
| Organisation | CSIR-National Institute of Oceanography, Regional Centre |
| Address | CSIR-National Institute of Oceanography, Regional Centre, Visakhapatnam Visakhapatnam, Andhra Pradesh, India Pincode: 530017 E-mail: alfisas44@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | Jellyfish swarms are ecologically dynamic but remain poorly studied in terms of diversity, interactions, and environmental drivers, especially in tropical monsoonal regions like the Bay of Bengal (BoB). This study explores jellyfish assemblages and ecological interactions during a Pelagia noctiluca swarm in the coastal BoB during the southwest monsoon, focusing on how environmental factors and trophic dynamics shape jellyfish and mesozooplankton (MZ) assemblages. Hydrographical data revealed non-significant variations in water temperature and salinity between the shallow coastal zone (SCZ) and deep coastal zone (DCZ). Elevated nutrient concentrations in the DCZ sustained dense P. noctiluca swarms. Dissolved oxygen (DO) levels were lower in the DCZ, likely due to metabolic oxygen consumption by larger jellyfish taxa. MZ abundance was notably higher in the DCZ (1208 ± 150 ind./m³) than in the SCZ (916 ± 95 ind./m³), exerting top-down trophic pressure that lowered chlorophyll a (Chl a) concentrations in the DCZ, while the SCZ exhibited higher Chl a levels. A total of 30 jellyfish species were identified, including Hydromedusae (11 species), Siphonophorae (13 species), Scyphozoa (1 species), and Ctenophora (5 species), making this the first comprehensive documentation of jellyfish diversity during a scyphozoan swarm in the BoB. Niche partitioning played a key role in jellyfish coexistence, easing competition and predation. Smaller taxa like hydromedusae and siphonophores dominated the SCZ, while larger ctenophores and scyphozoans were more common in the DCZ. P. noctiluca swarms notably influenced jellyfish assemblage patterns and trophic dynamics, with broader implications for pelagic food webs, nutrient flow, and fisheries. |
| Are you part of IIOE-2 endorsed project | no |
| Keywords | Ctenophora, Hydrozoa, Marine Ecosystems, Pelagia noctiluca, Scyphozoa, Taxonomy. |
| For Awards | yes |
| Date Of Birth | 07-02-1993 |
| ECSN Registration Number | IIOE2-ECSN-0147 |