The Mediterranean Sea Large Marine Ecosystem (LME) is characterized by its temperate climate. It is a semi-enclosed sea with several distinct biogeographical sub-units. It is bordered by a high number of countries. Intensive fishing is the primary force driving the LME, with eutrophication as the secondary driving force.

Productivity

The Mediterranean Sea has a narrow continental shelf. For the origin and history of the Mediterranean and Adriatic Seas, see Bombace, 1993. The LME presents a composite structure of environmental conditions, with local areas of upwelling, wind-driven currents, high water temperatures at least in some periods of the year, and nutrient inputs from rivers and human activities (see Caddy, 1993). The major inflow into the Mediterranean is nutrient-poor, oxygenated Atlantic surface water through the Strait of Gibraltar, resulting in generally well-oxygenated bottom waters.

Gyres and upwellings contribute to the Adriatic Sea’s high phytoplankton productivity. The highest levels of productivity occur along the coasts, near major cities, and at river estuaries. The lowest levels occur in the southeastern Mediterranean (see Darmouli, 1988). The Mediterranean has unusual biodiversity for a temperate sea (see FAO, 2003). Temperature stratification can occur during extended periods of calm seas, high temperatures, and inflows of freshwater. This separates the warmer, less saline surface water from the deeper, colder and more saline water, resulting in autumnal algal blooms and extended hypoxia or anoxia.

Fish and Fisheries

This is one of the most diverse and stable LMEs in terms of species groupings and their share in the total catch. The Food and Agriculture Organization (FAO) 10-year capture trend (1990-1999) shows stable catch trends in recent years, with a moderate increase in shelf catch, from under 1 million tons in 1990 to 1.1 million tons in 1999 (see FAO, 2003, figure 20). Clupeoids (herrings, sardines and anchovies) form the most important species group with 38% of catch. Miscellaneous coastal fishes account for 18% of the catch, and mollusks for 16%. For more information on primary production and fisheries, see Caddy, 1993. For a study on ecology and fisheries in the Adriatic Sea, see Bombace, 1993. Technological improvements in the fishing fleet and increased fishing capabilities have resulted in a decline in the catch rate per boat (see Caddy, 1993). Fishing effort has increased in response to high fish prices. By the 1970s, a substantial portion of the less productive southern shelves was being harvested for demersal resources. This also involved distant-water trawlers, with the result that demersal resources were fished at close to maximum sustainable yield. In the Adriatic Sea, coastal pollution and eutrophication have been the principal factors driving change in fisheries yields. Fish kills have occurred in the northern Adriatic as a result of noxious phytoplankton blooms and anoxic conditions.

Pollution and Ecosystem Health

There are concerns over the decline, especially in the northern Mediterranean, of fish species and species diversity. Negative anthropogenic impacts on fisheries are untreated sewage and an increased incidence of toxic blooms. However, quantifying these effects and establishing the respective contributions of overfishing and eutrophication are problematic (see Caddy, 1993). Blooms of phytoplankton and benthic diatoms have resulted in local fish kills caused by anoxia. Planktonic blooms and sewage contamination of coastal waters have also caused health problems associated with the ingestion of contaminated shellfish (see UNEP/FAO, 1990; and Caddy, 1993). Major threats to the biodiversity of the region’s coastal and wetland ecosystems are: uncontrolled development, urbanization, and especially pollution from land-based sources such as industry, human sewage and agriculture, which enter the Mediterranean via runoff, discharge, and river transport. The atmosphere contributes nitrogenous compounds, contaminants, and heavy metals (see Caddy, 1993; and UNEP, 1989).

Socioeconomic Conditions

The Mediterranean Sea’s 26,000 kilometers of coast supports a population estimated at 132 million inhabitants. The figures swell in the summer months, as tourists flock to the region, attracted by its cultures and pleasant climate. The continuous increase of tourists and settlers is a boon to the region, and is today of higher economic value than fisheries in many Mediterranean countries (see Caddy, 1993). But tourism is also causing environmental degradation through extensive development, added pressure to the coastal areas, and stress on the marine environment. The region, situated at the crossroads of Africa, Europe and Asia, has a high diversity of cultures, countries, political systems, and religions. It contains major population centers and industrial activities. Numerous fishing ports are dispersed along the Mediterranean coastline. For a historical perspective on fisheries in the Mediterranean Sea, see Caddy, 1993. Fisheries production has increased in many areas and is of major economic importance. Mariculture has increased production figures for mussels and oysters. Anthropogenic nutrient enrichment and eutrophication caused by runoff and polluted river discharges are a concern both for fisheries and tourism revenues.

Governance

Governance of the Mediterranean Sea LME involves a high number of countries (20 countries). They differ in their stage of economic and institutional development and in their capacity to address biodiversity issues in the context of sustainable development.

References

Articles and LME Volumes •Bombace, Giovanni. 1993. "Ecological and Fishing Features of the Adriatic Sea," in Kenneth Sherman, et al. (eds.), Large Marine Ecosystems: Stress, Mitigation, and Sustainability (Washington, D.C.: American Association for the Advancement of Science, 1993) pp. 119-136. ISBN: 087168506X. • FAO, 2003. Trends in oceanic captures and clustering of large marine ecosystems—2 studies based on theFAO capture database. FAO fisheries technical paper 435. 71 pages. • Caddy, John F. 1993. "Contrast Between recent Fishery Trends and Evidence from Nutrient Enrichment in Two Large Marine ecosystems: The Mediterranean and the Black Seas," in Kenneth Sherman, et al. (eds.), Large Marine Ecosystems: Stress, Mitigation, and Sustainability (Washington, D.C.: American Association for the Advancement of Science, 1993) pp. 137-147. ISBN: 087168506X.

Other References •AA, V., 1996. Strategy for the Protection of the Mediterranean Monk Seal Monachus monachus in Greece.Archipelagos-Mom, Athens. •Artegiani, A. 1984. Seasonal Flow rates of the Italian rivers having outlets in the Northern and the Central Adriatic. FAO Fish. Rep. 290:81-83. •Artegiani, A. 1987. Parametriabientali, dinamica delle acque costiere, della produtt, primaria, delle caratt, geomorfol,e fisionomiadella fascia costiera marchigiana. Report for the Marche Region. •Azov, Y. 1990. Eastern Mediterranean: A marine desert? Mar. Pollut. Bull. 23:225-232. •Caddy, J.F. 1990. Recent trends in Mediterranean fisheries. In: Recent trends in the fisheries and environment in the General Fisheries Council for the Mediterranean (GFCM) area. Pp.1-42. Ed. by J.F. Caddy and R.C. Griffiths. GFCM Studies and Reviews. No. 63. Food and Agriculture Organization of the United Nations (FAO), Rome. ISBN: 9251030332. •Degobbis, D. 1989. Increased eutrophication of the Northern Adriatic Sea. Marine Pollution Bulletin 20(9):452-457. •Fabi, G. and Fiorentini, L. 1989. Shellfish culture associated with artificial reefs. FAO Fish. Rep. 428:99-107. •Fredj, G, Bellan-Santin, D, and M. Meinardi, 1992. Etat des connaissances sur la faune marine mediterraneenne. In: D. Bellan (ed), Speciation et biogeographie en mer Mediterranee, Bull. Inst. Oceanogr. Monaco, no. sp. 9, 133-145 p. •Friligos, N. 1989. Nutrient status in the Aegean waters. Appendix V. In: FAO Fish. Rep.. No. 412. Pp.190-194. Doc. FIPL/R412. FAO, Rome. •Garibaldi, L. and J.F. Caddy, 1998. Biogeographic characterization of Mediterranean and Black Seas faunal provinces using GIS procedures. Ocean and Coastal Management 39:211-227. •GFCM. 1989. General Fisheries Council for the Mediterranean, Statistical Bulletin No. 6. FAO, Rome. •Hannesson, R. 1989. Optimum fishing effort and economic rent: A case study of Cyprus. FAO Fish. Tech. Paper No. 299. FAO, Rome. ISBN: 9251027536. •IMO/UNEP, 1998. Regional Information System. Part C. Databanks, Forecasting Models and Decision Support Systems, Section 4, List of Alerts and Accidents in the Mediterranean. REMPEC, Malta. •Josupeit, H. 1987. Prices and demand for small pelagic fish in Mediterranean countries. DOC.GFCM:SP/III/87/Inf.FAO, Rome. •Kapetsky, J.M. 1984. Coastal lagoon fisheries around the world. Some perspectives of fishery yields, and other comparative fishery characteristics. GFCM Studies and Reviews. No. 61. •Mediterranean Action Plan, 1999. Strategic Action Programme (SAP) to address pollution from land-based activities. Athens. 164 pages. •NSF/NASA. 1989. Ocean Color from Space. A folder of remote sensing imagery and text prepared by NSF/NASA-sponsored U.S. Global Ocean Flux Study Office, Woods Hole Oceanographic Institution, Woods Hole, MA. •Savini, M. and Caddy, J.F. (eds.). 1989. Report of the second technical consultation on stock assessment in the eastern Mediterranean. FAO Fish. Rep. 412(FIPL/R412). FAO/Rome. •Tortonese, E. 1983. Distribution and ecology of endemic elements in the Mediterranean fauna (fishes and echinoderms). Medit. Mar. Ecosyst. NATO Conf. Ser.:57-83. •UNEP. 1982. Achievements and planned development of UNEP’s Regional Seas Program and comparable programs sponsored by other bodies. UNEP Regional Seas Reports and Studies. No.1. UNEP, Nairobi. •UNEP. 1989. State of the Mediterranean marine environment. The Mediterranean Action Plan. Technical Report. No. 28. UNEP, Nairobi. •UNEP/MAP, 1993. Repertoire des 55 Sites Proposes pour la protection. RAC/SPA, Tunis. UNEP, RAC/SPA, 1994. Directory of Marine and Coastal Protected Areas of the Mediterranean Region. 
Sites of Biological and Ecological Value. •UNEP, 1997. Identification of Priority Pollution Hot Spots and Sensitive Areas in the Mediterranean. UNEP, Athens. •UNEP (OCA)/MED WG, 1999. Draft Reference Classification of Marine Habitat Types for the Mediterranean Region. 154/CRP 1. Addendum 4,5,6. •UNEP, RAC/SPA, 1999. Indicators of Marine and Coastal Biodiversity of the Mediterranean Sea. •UNEP/FAO. 1990. Final reports on research projects dealing with eutrophication and plankton blooms (Activity H). MAP Technical Reports Series. No. 37. UNEP, Nairobi. •Vallega, A, 1998. Integrated coastal area management in the framework of the UNEP regional seas programme: the lesson from the Mediterranean. Coastal Management. The University of Chicago Press. Pp. 245-278. •Vucetic, T. 1988. Long-term (1960-1983) fluctuations of zooplankton biomass in the Palagruze-Gargano area. FAO Fish. Rep. No. 394 (FIPL/R394). FAO/Rome.

Adapted from (2008). Mediterranean Sea large marine ecosystem. Retrieved from http://www.eoearth.org/view/article/154549 Published: March 24, 2008, 2:23 am Topic Editor: J. Emmett Duffy Source: NOAA