Performance of large-scale stow nets for investigating jellyfish

Jellyfish blooms have become more frequent and hazardous to the ecosystem, fisheries, facilities, and tourism. However, capturing jellyfish and preserving their integrity can be challenging due to their gelatinous, soft, and fragile nature. In this study, we evaluated the performance of several stow nets for sampling different jellyfish species. We found that tailored sampling gears were necessary to minimize injuries during large-scale net sampling processes. Specifically, bursiform-type nets were superior for harmlessly sampling small medusae of both species and large medusae of Aurelia coerulea , while a plane-type net with a 100-mm mesh size was more effective for capturing large medusae of Nemopilema nomurai . The results suggested that stow nets could collect large quantities of jellyfish samples while preserving their integrity, making them an effective tool for investigating jellyfish. Our findings allowed us to precisely evaluate the correlation between jellyfish bell diameter and wet weight, which can provide accurate population estimates for further studies. It may also significantly improve the sample size of jellyfish and make the verification process for acoustics and other techniques more accurate.