Difference between revisions of "Pollution and pelagic fish"
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| − | Fish are continuously in | + | Fish are continuously in contact with their environment through their gills . Therefore, unlike [[pollution and sea birds|sea birds]] and [[pollution and marine mammals|marine mammals]], they can adsorb contaminants from their environment. Fish can therefore both be contaminated by eating and by direct uptake from the water. As they form the top of the food chain, large carnivorous fish will also experience problems from [[biomagnification|biomagnifying]] substances like [[methylmercury]] and [[organochlorine compounds]].<ref>↑ Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp</ref> |
<u>'''Heavy metals'''</u> | <u>'''Heavy metals'''</u> | ||
| − | + | The presence of high concentrations of [[heavy metals]] forces the fishes to produce [[metallothioneins]]. The energy they have to spend on the production of these detoxifying proteins can no longer be used on growth or reproduction. | |
| − | + | Although adult marine fishes are thought to be rather protected from the effects of heavy metal concentration, the embryos and gametes are quite vulnerable. <ref name = pub2>Fishes in Estuaries: M. Elliott, K.L. Hemingway (Eds.); Blackwell Science, Oxford, 636 pp</ref> Combined with the variety (sub-)lethal effects, which heavy metals are known to have on fish, even non toxic concentrations of heavy metals can have a detrimental effect of fish stocks.<ref>Sinderman, C.J. 2006. Coastal Pollution: Effects on Living Resources and Humans. CRC Press, Boca Raton, FL. 280 pp</ref> | |
| − | Although adult marine fishes are thought to be rather protected from the effects of heavy metal concentration, the embryos and gametes are quite vulnerable. <ref name = pub2>Fishes in Estuaries: M. Elliott, K.L. Hemingway (Eds.); Blackwell Science, Oxford, 636 pp</ref> | ||
<u>'''Organochlorine compounds'''</u> | <u>'''Organochlorine compounds'''</u> | ||
Revision as of 10:38, 20 July 2009
Fish are continuously in contact with their environment through their gills . Therefore, unlike sea birds and marine mammals, they can adsorb contaminants from their environment. Fish can therefore both be contaminated by eating and by direct uptake from the water. As they form the top of the food chain, large carnivorous fish will also experience problems from biomagnifying substances like methylmercury and organochlorine compounds.[1]
Heavy metals
The presence of high concentrations of heavy metals forces the fishes to produce metallothioneins. The energy they have to spend on the production of these detoxifying proteins can no longer be used on growth or reproduction. Although adult marine fishes are thought to be rather protected from the effects of heavy metal concentration, the embryos and gametes are quite vulnerable. [2] Combined with the variety (sub-)lethal effects, which heavy metals are known to have on fish, even non toxic concentrations of heavy metals can have a detrimental effect of fish stocks.[3]
Organochlorine compounds
Organochlorine pesticides very often caused acute toxic effects in fish in the 1960s. As they were sprayed on agricultural areas near the coast, the pesticides tended to ended up in large doses in nearby bays, resulting in massive local fish mortalities. This caused fisheries for instance in the Laguna Madre, a bay in Texas, to collapse. [4] When present at lower concentrations which don't cause acute toxicity, these organochlorines can also accumulate in the fishes. It is thought that these can lead to various sublethal effects. In the Elbe estuary in Germany chronic exposure might have resulted into reduced productive success, damage to the liver, kidneys and intestines in fishes.[2]
Case studies
Case study 1:Effects of xenoestogens in eels[5]
References
- ↑ ↑ Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp
- ↑ 2.0 2.1 Fishes in Estuaries: M. Elliott, K.L. Hemingway (Eds.); Blackwell Science, Oxford, 636 pp
- ↑ Sinderman, C.J. 2006. Coastal Pollution: Effects on Living Resources and Humans. CRC Press, Boca Raton, FL. 280 pp
- ↑ Clark, R,B., 1999. Marine pollution. Oxford University press, Fourth edition, pp 161
- ↑ Versonnen, B.J.; Goemans, G.; Belpaire, C.; Janssen, C.R. (2004). Vitellogenin content in European eel (Anguilla anguilla) in Flanders, Belgium. Environ. Pollut. 128(3): 363-371
