Listed below is background material on the Gulf of Mexico Large Marine Ecosystem. To keep this site up-to-date, users are requested to provide relevant information or links to the LME webmaster .  

For this GEF Project, a Transboundary Diagnostic Analysis and Strategic Action Program is being developed.

BRIEF  DESCRIPTION:

This LME is characterized by its tropical climate. The Gulf of Mexico is partially isolated from the Atlantic Ocean. Important hypotheses concerned with the growing impacts of pollution, overexploitation, and environmental changes on sustained biomass yields are under investigation for this LME. Intensive fishing is the primary force driving the LME, with climate as the secondary driving force. LME books and articles pertaining to this LME include Richards and McGowan, 1989, Dagg et al., 1991, Brown et al., 1991, Kumpf, Steidinger and Sherman, 1999, and Schipp, 1999. The Global Environment Facility (GEF) is supporting an LME project in the Gulf of Mexico to address critical threats to the coastal and marine environment, and to promote ecosystem-based management of coastal and marine resources. For an introduction to the Gulf of Mexico Large Marine Ecosystem, review the Gulf of Mexico Program , sponsored by the U.S. Environmental Protection Agency.

I. PRODUCTIVITY:

The continental shelf is topographically diverse, and includes slopes, escarpments, knolls, basins and submarine canyons (for more information on the physical oceanography of the Gulf of Mexico, see Wiseman et al, 1999). Ocean waters enter from the Yucatan channel and exit from the straits of Florida, creating the loop current which is associated with the upwelling and the high level of nutrients flow of this LME (for more information on what controls primary production in this LME, see Lohrenz et al, 1999). There is an additional major fresh water source, from rivers in the USA and from Mexico. Productivity ranges from eutrophic conditions in coastal waters to oligotrophic in the deeper ocean. Overall, The Gulf of Mexico Large Marine Ecosystem is considered a Class II, moderately productive (150-300 gC/m2-yr), ecosystem based on SeaWiFS global primary productivity estimates. The productivity of the LME is complex. Lohrenz et al, 1999 distinguish between local scale, mesoscale, and synoptic scale processes.
Local scale processes include small river and estuarine flow, wave effects and near shore circulation. Mesoscale processes include tides, upwelling, meteorological forcing, topographic effects, large river flow, and Loop Current circulation features. Synoptic scale processes include seasonal variations in solar and atmospheric conditions, and Loop Current excursions. The region of the Mississippi River outflow has the highest measured rates of primary production in the Gulf of Mexico LME (see Sklar and Turner 1981; Lohrenz et al., 1990). Hurricanes may increase phytoplankton biomass and primary production because they increase the vertical advection of nutrients into surface waters (see Iverson, 1977).

II. FISH AND FISHERIES:

 The NOAA/NMFS Southeast Region includes statistics for both this LME and the Southeast US Continental Shelf LME (see Our Living Oceans, 1999, and the NMFS Southeast Fisheries Science Center.  For landings of mackerel, variations in reef fish landings, shrimp, blue crab and menhaden, specific to the US Gulf of Mexico, see Our Living Oceans, 1999. Reef fish include groupers, snappers, amberjacks and triggerfish. Red grouper is the most important commercial species of reef fish off the west Florida coast. Red snapper is apparently the most overfished species in the Gulf of Mexico (Goodyear, 1996). Shrimp fisheries use small mesh nets, with a resulting bycatch of non-target and/or under-size red snappers, croakers, sea trouts and sea turtles. Sea turtles are listed as endangered or threatened under the Endangered Species Act. For fishery management plans in the US Gulf of Mexico, see Our Living Oceans, Appendix 2. The management of king mackerel has been successful in increasing the fish biomass, but the goal of recovering the stock has not yet been accomplished. There is a Gulf of Mexico fishery management council for this LME (see the Gulf of Mexico Fisheries Management Council).  The Gulf of Mexico LME is bordered by 3 countries: the USA, Cuba, and Mexico. The FAO 10 year trend (click on figure below) shows a predominance of herrings, sardines, anchovies, representing almost 60% of the LME catch percentage (see FAO 2003). The catch was 900,000 tons in 1990, and up to 1 million in 1999, with a low in 1992 and a peak in 1994. See also detailed fish catch statistics available for this LME, made available by the University of British Columbia Fisheries Center. For a status of exploited fish species in the Gulf of Mexico, see Shipp, 1999. The long term harvesting effects on coral reefs are not well understood and will require cautious management. The removal of apex predators from coral reefs may result in shifts in species composition. For information on fisheries management in Mexico, see Arreguin-Sanchez et al, 1999. .

 
III.  POLLUTION and ECOSYSTEM HEALTH :

The Gulf of Mexico LME shows signs of ecosystem stress, in bays, estuaries, and coastal regions (see Birkett and Rapport, 1999). There is shoreline alteration, pollutant discharge, oil and gas development, and nutrient loading. The overall condition for the USA section of this LME, according to the EPA’s 7 primary indicators is: good dissolved oxygen; fair water quality; poor coastal wetlands, poor eutrophic condition, poor sediment, benthos and fish tissue. (EPA, 2001 has maps and figures for the US Gulf Coast). Coastal wetland loss is currently about 5% per decade. Fish condition is poor, with several consumption advisories for this LME. There have been incidents of mercury contamination of fishery resources. For an assessment of ecologic stresses and information about ecosystem health, see Kumpf, Steidinger and Sherman, 1999. Large hypoxic areas have been detected in this LME (see Rabalais et al, 1999). The Mississippi-Atchafalaya River Basin and Gulf of Mexico hypoxic zone is the largest zone of anthropogenic coastal hypoxia in the western hemisphere. It occurs where the Gulf of Mexico waters receive the flow of the Mississippi-Atchafalaya River basin. Hypoxia occurs below the fresh-water driven pycnocline from late February through early October, but it is most widespread, continuous, and severe in June, July, and August. (Rabalais, 1999).  The nutrients delivered from the watershed foster large-scale phytoplankton production (see report of the National Science and Technology Council Committee on environment and natural resources).  See also the “Action Plan for reducing, mitigating, and controlling hypoxia in the Northern Gulf of Mexico”, by the Mississippi River/Gulf of Mexico watershed nutrient task force.  A goal is to reduce the area to less than 1,930 miles by the year 2015.All partners will implement actions aimed at achieving a 30% reduction in nitrogen discharges to the Gulf. Wetlands will be created and restored. Other goals are to increase the efficiency of agricultural and urban non point source nutrient management practices, and upgrade sewage treatment facilities for nitrogen removal. For oil pollution, see Gold-Bouchot et al, 1999.  The Council for Agricultural Science and Technology (CAST) has produced a report for this LME.

IV. SOCIOECONOMIC CONDITIONS:

The Gulf of Mexico LME is a major asset to the three surrounding countries, in terms of fisheries, tourism, agriculture, oil, infrastructure, trade and shipping (see Cato and Adams, 1999). Commercial fishing is an important component of the LME’s economy. It contributed  $630 million to the USA in 1993. The US Gulf region contains one-fourth of the U.S. seafood processing and wholesale establishments. Marine sport-fishing is another industry of regional importance, providing jobs and recreational activities. Species of economic importance in the Mexican part of the Gulf of Mexico LME include brown shrimp, white shrimp, pink shrimp, octopus, red grouper, and the brackish water clam. Octopus is currently being exploited by an artisanal fleet, and by a middle-sized fleet (see Solis et al., 1995). In the USA, the infrastructure for oil and gas production in the Gulf of Mexico (oil refineries, petrochemical and gas processing plants, supply and service bases for offshore oil and gas production units, platform construction yards and pipeline yards) is concentrated in coastal Louisiana and eastern Texas. Oil production has an impact on other environmental and economic resources. The Gulf of Mexico LME contains major shipping lanes. Port facilities contribute to important sources of employment. The volume and value of shipping has increased in the Gulf region (see Cato and Adams, 1999). Population along the US coast increased by 52% between 1970 and 1990, and is currently around 4 million people. For the socioeconomic effects of hypoxic conditions in the Gulf of Mexico, see the Gulf of Mexico Hypoxia Assessment Report.

V. GOVERNANCE:

A project proposal has been developed for this LME by marine resource experts from Mexico, Cuba and the United States. The result will be a Transboundary Diagnostic Analysis and Strategic Action Programme. Its objective is to enhance national and regional efforts to address top priority environmental and living resource issues in the LME. A new approach is needed in order to conserve the living resources and habitats of this LME, as well as protect it from pollution. Legal, policy and institutional reforms will be developed to address the major threats to ecosystem sustainability. There is no current institutional arrangement for cooperation between the 3 countries. In 1998, the US Congress passed the Harmful Algal Bloom and Hypoxia Research and Control Act, which contained specific requirements for addressing hypoxia in the Gulf of Mexico (see under Ecosystem Health). For more information on management and governance, see Kumpf, Steidinger and Sherman, 1999. See the Florida Department of Environmental Protection (DEP) initiative in ecosystem management.   The EPA's National Estuary Program (NEP) supports six projects along the Gulf of Mexico. View the National Coastal Condition Report for more information.  The National Marine Fisheries Service (NMFS) Southeast Regional office provides technical and administrative support to the Gulf of Mexico Fishery Management Council (Gulf Council) , one of eight established by the Magnuson-Stevens Fishery Conservation and Management Act.  The Gulf Council prepares fishery management plans for species in the US waters of the Gulf of Mexico.