The Impact of the Deepwater Horizon Spill on Commercial Blue Crab Landings

We examine the effects of the Deepwater Horizon oil spill on landings, revenues, and effort in the commercial blue crab fishery. A key contribution of our work is that it goes beyond simple pre-post analysis and uses a difference-in-differences method to identify the causal effects of the spill. We compare affected areas to two different counterfactuals—Atlantic states, as well as Louisiana basins that were less exposed to the spill—which essentially provides upper and lower bounds on the magnitude of the impact. When using the Atlantic as a counterfactual for the Gulf states, we find that the spill resulted in a 75–85 percent decrease in landings in the months immediately following the spill, followed by a relatively swift recovery. While there is some evidence of potential longer term impacts, we cannot estimate these effects precisely. Because of the potential for substitution between Gulf and Atlantic blue crab, we view these results as an upper bound on the true impact. When comparing Louisiana basins that were more versus less affected by the spill, we identify a 50 percent drop in blue crabbing trips in basins that were more affected following the spill; however, we find little impact on landings, likely because the spill and the resulting closures changed the relationship between effort (trips) and landings. Overall, our findings suggest that the Deepwater spill did result in substantial, short-term losses to the blue crab fishery, but that the fishery also exhibited a high degree of resilience and recovered quickly as soon as the closures were ended.