Potential population and economic consequences of sublethal injuries in the spiny lobster fishery of the Florida Keys

Abstract

Animals that interact with but are not retained by fishing gears may later die. The population and economic consequences of these sublethal fishery interactions are seldom known but may be significant. In the present study, a population model was used to quantify potential population and economic consequences of injuries that Caribbean spiny lobsters (Panulirus argus) sustain from fishing activities in the Florida Keys, USA. Injuries generated by the fishery are known to reduce growth and elevate mortality. Simulation modelling results indicated that injuries may reduce adult lobster abundance and associated landings by ≥50% in areas with high recreational fishing effort. When simulated injuries were ~20 times lower (representing areas with lower fishing effort), these injuries were only responsible for a 5 and 8% reduction in the adult lobster population and commercial landings respectively. Important parameters within the model (growth, time in stage and mortality of injured lobsters) were altered by ±10% to assess model sensitivity. Final results changed <10% (with the exception of one 15% change), suggesting that model output was relatively insensitive to variation in key parameters. When the impact of sublethal injuries was applied to the entire spiny lobster fishery in the Florida Keys, adult stock biomass and annual commercial landings were reduced by 900 and 160 t (US$1.6 million) respectively. These results suggest that sublethal fishery interactions can lead to high population and economic losses, and highlight the need to incorporate sublethal injuries into stock assessments and economic models.