Oil And Fisheries In The Gulf of Mexico
The explosion of the Deepwater Horizon offshore drilling rig on April 20, 2010 initiated the world’s largest known oil spill in the Gulf of Mexico Large Marine Ecosystem (LME). Characterized by an extensive continental shelf and substantial nutrient input from rivers and Loop Current-induced upwelling, this region is valued for its high productivity and lucrative fisheries. According to the United States National Marine Fisheries Service, approximately 18% of the U.S. domestic commercial fisheries landings reported in 2009 originated in the Gulf of Mexico. Estimates of the quantity of oil, natural gas and associated methane, and chemical dispersants released as a result of this calamity have been plagued by uncertainty. The U.S. Government-appointed team of scientists, the Flow Rate Technical Group, estimated that a total of 4.9 million barrels of oil were released from BP’s Macondo well, while the results of an independent study suggest that between 4.16 and 6.24 million barrels leaked from the well. Additionally, according to BP’s records, approximately 1.8 million gallons of dispersant were applied at the site of the leak as well as the sea surface. Complex oceanographic processes have made it difficult to determine the current and future distribution of these substances from the surface to the sea floor and their persistence in the marine environment. Most importantly, there is no immediate answer to questions concerning short-term and long-term impacts on habitats and marine organisms in the path of this disaster. The capacity of habitats and species to recover from the effects of oil, methane, and dispersants may have already been compromised due to pre-existing sources of stress. Since the 1950s, heavy fertilizer use within the Mississippi River drainage basin, encompassing 41% of the contiguous United States, has led to increased nitrate loading in the northern Gulf of Mexico. This nutrient-laden, freshwater discharge ultimately results in the formation of periodic, oxygen-depleted “dead zones” devoid of fish, shrimp, and most other invertebrates in shelf waters off the coasts of Mississippi, Louisiana, and eastern Texas. Also, the extensive shrimp trawl fishery in the Gulf of Mexico directly impacts many species of fish and invertebrates due to habitat destruction and bycatch mortality. This uncertainty is particularly troubling for commercial fisheries. While it is difficult to predict the impacts of an oil spill of this magnitude on the future of fisheries in the region, we can infer possible effects by investigating broader patterns. This study presents an analysis of the prespill spatial distribution of commercial fisheries catch and landed value in the Gulf of Mexico LME relative to the post-spill fisheries closure in an effort to evaluate potential economic losses.