Spatial patterns in species assemblages associated with the Northwestern Gulf of Mexico shrimp trawl fishery

Abstract

The shrimp trawl fishery in the Gulf of Mexico (GOM) removes a diverse community of bycatch species from the Gulf Large Marine Ecosystem (LME). A small fraction of the discarded species is economically important, and little is known about the majority of bycatch species. Large-scale fishery-independent trawl surveys from the Southeast Area Monitoring and Assessment Program (SEAMAP) were utilized to examine the spatial dynamics of the demersal fish community associated with the shrimp trawl fishery across the northwest GOM-LME. Multi-variate analyses revealed 3 distinct demersal fish communities from the fall survey and 4 distinct communities from the summer survey. Shrimp Statistical Zone 13, nearest the Mississippi River, was a differentiating factor between the 2 surveys, associating with Zones 14 and 15 in the fall survey, and comprising its own dissimilar community in the summer survey. The dominant species within each zone differed between the summer and fall seasons, which can be explained by the time of spawning and seasonal ontogenetic migrations of species asso - ciated with the survey. Indicator species analysis identified species in each season and region that can be used to monitor future ecosystem changes within these regions. (Figure Presented)