Impact of mesh size change on catch size composition of splendid alfonsino Beryx splendens in the Emperor Seamounts

In 2019 the NPFC made changes to the regulations of trawl net codend mesh sizes used for fishing splendid alfonsino Beryx splendens in the Emperor Seamounts. Intended to reduce the fishing pressure on immature individuals, initial evaluation of size composition data found no change following the implementation of the new regulations. Here we reevaluate the impact of the implemented mesh changes on alfonsino using a more robust size composition dataset spanning from 2013 to 2023, while also comparing the effects of different seamounts, fishing vessels, and seasons. Our analysis found a weakly positive relationship between the mesh changes and an increase in mean alfonsino FL over time, but there are several unusual length frequencies related to fishing vessel or year. While there is some evidence to support the mesh size regulations and reduced fishing pressure are having a positive effect, continued monitoring to determine the validity of the current trend is necessary.