Bycatch species distribution from mid-water trawlers in the north-eastern Arabian sea: a step towards the implementation of marine spatial planning

Abstract

Spatial conservation planning to reduce the impact of fishing on ecosystems necessitates understanding of the spatial distribution of bycatch in fishing grounds. Management measures in Indian waters cannot be spatially explicit without this information. Thus, a preliminary study was conducted on the northwest coast of India to identify the most persistent bycatch areas from mid-water trawlers targeting largehead hairtails (Trichiurus lepturus). Semi-variogram modelling and kriging interpolation showed that bycatch abundance varied by species and associated habitat or depth preference. A significant positive correlation between species in bycatch abundance revealed that few share the same habitat in the region. Bycatch species were concentrated in the inshore area (<70 m depth) during the post-monsoon and summer seasons, but their densities reduced in the winter. The bycatch distribution map aid in the future implementation of spatial management measures, such as the designation of the no-fishing zone and conservation networks.