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The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems
- Source :
- ICES Journal of Marine Science. 57:476-494
- Publication Year :
- 2000
- Publisher :
- Oxford University Press (OUP), 2000.
-
Abstract
- Stevens, J. D., Bonfil, R., Dulvy, N. K., and Walker, P. A. 2000. The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems. – ICES Journal of Marine Science, 57: 476–494. The impact of fishing on chondrichthyan stocks around the world is currently the focus of considerable international concern. Most chondrichthyan populations are of low productivity relative to teleost fishes, a consequence of their different life-history strategies. This is reflected in the poor record of sustainability of target shark fisheries. Most sharks and some batoids are predators at, or near, the top of marine food webs. The effects of fishing are examined at the single-species level and through trophic interactions. We summarize the status of chondrichthyan fisheries from around the world. Some 50% of the estimated global catch of chondrichthyans is taken as by-catch, does not appear in official fishery statistics, and is almost totally unmanaged. When taken as by-catch, they are often subjected to high fishing mortality directed at teleost target species. Consequently, some skates, sawfish, and deep-water dogfish have been virtually extirpated from large regions. Some chondrichthyans are more resilient to fishing and we examine predictions on the vulnerability of different species based on their life-history and population parameters. At the species level, fishing may alter size structure and population parameters in response to changes in species abundance. We review the evidence for such density-dependent change. Fishing can affect trophic interactions and we examine cases of apparent species replacement and shifts in community composition. Sharks and rays learn to associate trawlers with food and feeding on discards may increase their populations. Using ECOSIM, we make some predictions about the long-term response of ecosystems to fishing on sharks. Three different environments are analysed: a tropical shelf ecosystem in Venezuela, a Hawaiian coral reef ecosystem, and a North Pacific oceanic ecosystem. 2000 International Council for the Exploration of the Sea
- Subjects :
- 0106 biological sciences
Reef shark
Fishing
Population
Aquatic Science
Biology
Oceanography
01 natural sciences
Shark finning
EcoSim
Marine ecosystem
14. Life underwater
education
Ecology, Evolution, Behavior and Systematics
geography
education.field_of_study
geography.geographical_feature_category
Ecology
010604 marine biology & hydrobiology
04 agricultural and veterinary sciences
Coral reef
Discards
Fishery
040102 fisheries
0401 agriculture, forestry, and fisheries
Subjects
Details
- ISSN :
- 10543139
- Volume :
- 57
- Database :
- OpenAIRE
- Journal :
- ICES Journal of Marine Science
- Accession number :
- edsair.doi...........2b39e03441d33a268bf3e2b340bfe435