Jellyfish bloom: Abundance, distribution and impact analysis in the commercial dol net fishing ground of Northwest coast of India, Arabian Sea

Abstract

Globally, jellyfish blooms significantly impact commercial fishing operations, leading to revenue loss. This study investigated the biomass, distribution, seasonality, and hindrance intensity of Rhopilema hispidum (Vanhöffen, 1888) blooms in the Dol net fishery along the Palghar coast of the Arabian Sea. The experimental period for the single-day and multi-day dol net fishery during 2022-2023 revealed that R. hispidum blooms occurred in two main seasons: October-December and March-May, at depths of 10-40 meters. Estimated bloom biomass in multi-day dol net hauls ranged from 22.57 to 135.86 kg/hr/net, while single-day hauls ranged from 20.73 to 129.78 kg/hr/net. The fish-to-jellyfish catch ratio varied between 3.5:1.5 (October-December) and 2.25:2.75 (March-May) in the dol net catch composition. The fishers’ perception of the hindrance intensity of R. hispidum bloom with dol net fishing operation decreased in the following order: increased catch sorting time > painful sting > change in fishing ground > closure of fishing > clogging and bursting of nets > reduction in fish catches. Despite these challenges, R. hispidum blooms have the potential to develop jellyfish fisheries and offer new livelihood opportunities for local fishers.