Indirect effects of recreational fishing on spiny lobster (Panulirus argus) behavior, mortality and population dynamics

In this study, we quantified indirect effects within the Caribbean spiny lobsters (Panulirus argus) fishery in the Florida Keys, USA, including mechanisms that resulted in behavioral modification and lobster mortality, and potential population and economic consequences of these indirect effects. The spiny lobster fishery in the Florida Keys has intense recreational sport-diver effort during a 2d mini-season in which 80-90% of legal lobsters are removed from some areas, and an over capitalized commercial trap fishery where >900,000 lobster traps are deployed annually.; In field surveys we observed a 27% increase in the density of injured lobsters on patch reef habitats from before to after the 2 d mini-season, but not in other habitat types. In laboratory Y-maze shelter choice experiments, we observed that un-injured lobsters were less likely to shelter with injured lobsters than with un-injured lobsters. Using disturbance experiments conducted in the field we observed that disturbing and injuring lobsters on a coral patch-head caused individuals to emigrate from that patch-head before the mini-season, but had no effect on lobster density on patch heads after the mini-season. When lobsters were tethered in the field, mortality was higher when injured than uninjured. Similarly, lobsters that were exposed to triggerfish predators (Balistes capriscus) in a large seawater arena had a higher probability of mortality after being disturbed and injured.; We used an individual-based population model to quantify potential population and economic impacts of injuries lobsters receive from sport-divers in the Florida Keys. Model results suggest that the severity of population and economic impacts are dependent on the frequency of lobster injuries throughout the Florida Keys fishery. For example, areas associated with high densities of injured lobsters may have a ≥50% reduction in the abundance of adult lobsters and associated recreational and commercial harvests. In areas where the density of injured lobsters was ∼20 times lower, the impact of injuries on the adult lobster population and commercial landings was only 5 and 8%, respectively. Despite the seemingly smaller impact in areas with lower densities of injured lobsters, injuries may still be responsible for a 900 t reduction in the adult stock biomass and a 160 t, or {dollar}1.6 million reduction in annual commercial landings when scaled to the entire spiny lobster fishery in the Florida Keys. (Abstract shortened by UMI.)...