Using Electronic Logbook Data to Estimate the Impacts of the Deepwater Horizon Oil Spill on Shrimp Fishing Effort in the Gulf of Mexico

The BP Deepwater Horizon (DWH) oil spill began on 20 April 2010, discharging sufficient volumes of oil to result in closure of large areas of the federal waters of the Gulf of Mexico traditional penaeid shrimp fishing grounds.  The closure boundaries changed frequently in the first two months (19 times in May and June), after which changes occurred at approximately weekly intervals from July to October.  By November, the closure area had diminished to a relatively small area (2697 km²) near the well site.  We used National Marine Fisheries Service’s electronic logbook (ELB) and landings data in a Before-After/Control-Impact (BACI) design to estimate the effects of the closures on shrimp fishing effort for the shrimp fleets of the five Gulf states.  Texas and Alabama fleets did not exhibit significant changes in effort attributable to the closures, but significant reductions in shrimp fishing effort were observed for the Florida (50%; 95% confidence limits= 17-20%), Mississippi (93%; 88-96%), and Louisiana (45%; 20-60%) fleets.  Overall, the oil spill closures resulted in an approximate 65% (57-73%) reduction in penaeid shrimp effort during the second trimester of 2010, the period when large area closures were in effect.