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| | | Coastal and Marine Ecosystems |
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|  The physical modification of natural aquatic inland ecosystemsthrough the damming of rivers or the building of irrigation systems, for example, has often led to the creation of new ecosystems. These activities may also have unintended impacts on marine ecosystems, as seen in the example of the retention of nutrient-rich Nile waters through the building of the Aswan High Dam and the resulting collapse of the sardine fisheryin the Nile Delta.Ecosystems, on which fisheries depend, generally range from coastal areas to the open ocean, from tropical to polar oceans, including some semi-enclosed or enclosed seas. They include the lower end of river watersheds and their plumes, bays, estuaries and lagoons, coral and other reefs, continental shelves and slopes, and upwelling areas. | | |  Large Marine Ecosystems (LMEs)are relatively large regions (200 000 km2 or more) of the oceans characterized by distinct bathymetry, hydrography, productivity and trophically dependent populations. | | | | Neither pristine nor exploited ecosystems are static, but are subject to environmental variations. The frequency of these environmental changes and their amplitude vary widely. The greater and more frequent they are, the more significant the implications for productivity and for the management of fisheries. Natural variability adds to the uncertainty that should be considered in managing the harvesting of the resources of an ecosystem. A system's resilience to human impacts and their capacity to recover from serious disturbances varies with such natural cycles. | | | | Of particular significance is the El Niño Southern Oscillation (ENSO) phenomenon, a naturally occurring global climate cycle involving complex interactions between the surface of the ocean and the atmosphere in the tropical Pacific. El Niño (warm) and La Niña (cold) events are extreme phases on the ENSO cycle. It has been increasingly accepted that the ENSO phenomenon has a global impact. | | | | Fifty LMEs have now been identified extending across regions encompassing coastal areas from river basins and estuaries to the seaward boundary of continental shelves and the seaward margins of coastal current systems. | | | | |
 | | | | | | | Title | Monthly Mean Coastal Upwelling Indices, West Coast of South Africa 1981 to 2000
( DOCUMENT )
| | Author(s) / Editor(s) | Norton, J G; Schwing, F B; Pickett, M H; Cummings, S G; Husby, D M; Green Jessen, P. | | Description | Abstract (Shortened) Pacific Fisheries Environmental Laboratory (PFEL) Upwelling Index provides continuous proxy time series of coastal ocean processes for the study of surface layer physical and biological ocean dynamics. Nine locations from 15 deg to 36 deg South off the coast of southwest Africa. | | Keywords | WATER CIRCULATION; ECOSYSTEMS; NUTRIENT AVAILABILITY | | Geography Keywords | SOUTH WEST AFRICA; SOUTH EASTERN ATLANTIC | | Content Language(s) | English | |
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| Type of Document | Paper: Technical paper | | Document Status | Finished | | Publisher | US Department of Commerce | | Publication Location | Washington, DC | | Publication Date | September 2002 | | Hard Copy Availability | National Technical Information Service, 5285 Port Royal Road, Springfield, VA 22167 USA | | Series Title | NOAA Technical Memorandum NMFS | | Reference Info | | Number of Pages | 37 | Series ID | NOAA-TM-NMFS-SWFSC | Volume/Issue Number | 343 |
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1076 Topics - 5135 Related Knowledge - 2534 Members - 34 Editors |
