The effects of hypoxia on the northern Gulf of Mexico coastal ecosystem: A fisheries perspective

The northern Gulf of Mexico is an economically important coastal zone that produces large yields of fish and shellfish. Because of the documented impacts low oxygen can have on living resources, hypoxic bottom waters (< 2.0 mg l(-1)) that form along the coast are viewed as a threat to sustained fisheries production in the region. We reviewed factors related to fish habitat and production and evaluated potential effects of the hypoxia on nekton within this system. A complex set of environmental and anthropogenic factors impact nekton in the northern Gulf of Mexico. Fishery yields have remained strong for the northern Gulf over the last 40 years. Effects of hypoxia on distributions of nekton have been documented in the Gulf of Mexico. Also some changes in community structure of nekton are evident, although it is impossible to attribute any of the changes solely or specifically to hypoxia. Given the intensity and extent of hypoxia in the northern Gulf of Mexico other effects of hypoxia on nekton are probable. Nevertheless, we speculate that it is likely that other quantifiable impacts of greater magnitude may currently have more significant effects than hypoxia on the community structure and secondary production of nekton populations in the northern Gulf of Mexico, We hypothesize that the effects of hypoxia on the nekton in the northern Gulf may be buffered by characteristics of the basin, the fauna and the ecosystem. These characteristics may partially offset some of the negative impacts of hypoxia seen in other systems by providing spatial and temporal refuges for demersal nekton.