Effects of Live-Bait Shrimp Trawling on Seagrass Beds and Fish Bycatch in Tampa Bay, Florida

Roller trawling in turtlegrass beds along Florida's Gulf Coast for shrimp that are used as live bait may be destructive to seagrass beds and to juvenile fishes. The effects of a roller beam trawl on turtlegrass biomass and morphometrics during short-term, intensive trawls, and mortality of bycatch finfish captured in a trawl, were studied. Roller trawls were designed to reduce seagrass fragment collection, and no significant trawl impacts on turtlegrass were observed. Effects from repetitive trawling over longer time periods were not tested. Fish species differed in their susceptibility to trawl-induced mortality. Mortality and size were inversely related for many species. Small fish tended to be more susceptible than large fish to stress and mortality due to capture. Differential species mortality may alter fish diversity and composition relationships.