Symposium Abstract: Impacts to Coral Reef Benthos from Lobster Trap Gear in the Florida Keys National Marine Sanctuary
M. Chiappone, D. W. Swanson, and S. L. Miller
Growth in the Florida Keys fisheries for spiny lobster Panulirus argus and stone crab (Menippe mercenaria) has resulted in increased numbers of traps and environmental impacts. During 1998 alone, the stone crab and spiny lobster fisheries were estimated to utilize a total of 750,000 traps and 540,000, respectively. Impacts from gear are exacerbated when traps are lost due to severe storms. This study evaluated the distribution, density, and impacts to coral reef sessile invertebrates from lobster trap gear at 117 sites in the Florida Keys National Marine Sanctuary during 2000 and 2001. Sites were stratified according to benthic habitat type and fishing protection and encompassed 13 of the Sanctuary’s 23 no-fishing zones. Diver surveys using transects were performed to document the type, length, and number of biota impacted by lost gear. Surveys yielded 86 incidences of gear totaling nearly 380 m, consisting mostly of buoy lines and wood slats. Densities of gear among the three habitat types ranged from 0.11 to 0.86 incidences/100 m2, with four to eight times greater gear density in patch reefs compared to other habitats. The distribution of lobster trap gear did not differ significantly between protected and fished sites. Lobster trap gear, especially buoy lines, caused partial mortality or complete mortality to 152 sessile invertebrates. Relative to hook-and-line gear effects, lobster trap gear impacted sessile invertebrates varied less among the organisms considered. Gorgonians (39%) and scleractinian corals (24%) were the most commonly affected, followed by sponges (17%), colonial zoanthids (13%), and milleporid hydrocorals (7%).