Changes of lengths and maturity compositions in the catches and the relations with fishing tactics: A case study in splendid alfonsino, Beryx splendens, in Emperor Seamounts, North Pacific Ocean

Abstract

“Catch fewer juveniles and more adults”, approach of solving overfishing are easier said than done. Particularly for deepwater demersal fish, which generally exhibit greater susceptibility to fishing pressure, it is worthwhile conducting a comprehensive evaluation of fishing trends and the trends of the fish being caught to ensure sustainable fishery management. We investigated the trends of individual length and maturation compositions of the catches across various fishing operations to determine the effects of fishermen’s choices in the locations and/or time toward catch dynamics. Our study revealed that catch size/matured conditions were varied among vessels, and fishing depth, haul length, time, and geographical position were significantly related to the compositional dissimilarity of B. splendens catch. Overall, our study highlights the importance of considering not only the ecology of target organisms but also their surroundings, including human impacts, to achieve both future long-term conservation and sustainable use of demersal fish and the protection of marine ecosystems in this region.