Difference between revisions of "Pollution and pelagic fish"

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Fish are through their gills continuously in direct contact with their environment. Unlike [[pollution and sea birds|sea birds]] and [[pollution and marine mammals|marine mammals]] they can with these gills directly 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>
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[[Image:Diplodus_sargus.jpg|thumb|right|300px| <div style="text-align: center;">
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White seabream © J.G. Harmelin
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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 directly [[adsorption|adsorb]] contaminants from their environment. Fish (both [[pelagic]] as [[pollution and benthic fishes|benthic fish]]) can 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>
  
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Methylmercury can biomagnify to high values in large carnivorous fish. These fish are also more active, causing them to need more oxygen. To extract more oxygen, they have to pump more water through their gills, causing them also to adsorb more contaminants. Unlike marine mammals and (possibly) sea birds, fish can't demethylate methylmercury, nor can they excrete it efficiently. Therefore old carnivorous fish often contain very large amounts of methylmercury, making them unfit for human consumption.<ref name="pub">Clark, R,B., 1999. Marine pollution. Oxford University press, Fourth edition, pp 161</ref>
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The presence of high concentrations of [[heavy metals]] forces the fishes to produce [[metallothionein|metallothioneins]]. The energy they have to spend on the production of these detoxifying proteins can no longer be used on growth or reproduction.  
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Although adult marine fishes are thought to be rather protected from the effects of heavy metal concentration, the embryos and gametes remain 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>
  
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Organochlorine pesticides in the 1960s very often caused acute toxic effects in fish. This for instance caused fisheries in the Laguna Madre, a bay in Texas, to collapse. This was caused by pesticides sprayed on nearby agricultural areas. <ref name="pub">Clark, R,B., 1999. Marine pollution. Oxford University press, Fourth edition, pp 161</ref>
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[[Organochlorine pesticides]] have 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 end up in large doses in nearby bays, resulting in massive local fish mortalities. This caused fisheries for instance in Laguna Madre, a bay in Texas, to collapse. <ref name="pub">Clark, R,B., 1999. Marine pollution. Oxford University press, Fourth edition, pp 161</ref>
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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.<ref name = pub2>Fishes in Estuaries: M. Elliott, K.L. Hemingway (Eds.); Blackwell Science, Oxford, 636 pp</ref>
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Given the variety of (sub-)lethal effects, which these pollutants (organochlorines and heavy metals) are known to have on fish, even rather low, non toxic concentrations 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>
  
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Below you can find some links to Belgian case studies on ecotoxicology in pelagic fishes.
  
 
== Case studies ==
 
== Case studies ==
  
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Case study 1:[[Effects of xenoestrogens in eels]]<ref>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</ref>
  
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Case study 1:[[Effects of xenoestogens in eels]]
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==References==
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<references/>
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<ref>http://www.milieurapport.be/nl/feiten-cijfers/MIRA-T/milieuthemas/verspreiding-van-zware-metalen/zware-metalen-in-organismen-(uitgezonderd-mens)/zware-metalen-in-paling/</ref>
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{{author
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|AuthorID=19826
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|AuthorFullName=Daphnis De Pooter
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|AuthorName=Daphnisd}}
  
  
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==References==
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[[Category:Ecotoxicology]]
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<references/>
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[[Category:Coastal and marine pollution]]

Latest revision as of 15:33, 14 February 2024

White seabream © J.G. Harmelin

Fish are continuously in contact with their environment through their gills . Therefore, unlike sea birds and marine mammals, they directly adsorb contaminants from their environment. Fish (both pelagic as benthic fish) can 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 remain quite vulnerable. [2]

Organochlorine compounds

Organochlorine pesticides have 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 end up in large doses in nearby bays, resulting in massive local fish mortalities. This caused fisheries for instance in Laguna Madre, a bay in Texas, to collapse. [3] 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]

Given the variety of (sub-)lethal effects, which these pollutants (organochlorines and heavy metals) are known to have on fish, even rather low, non toxic concentrations can have a detrimental effect of fish stocks.[4]

Below you can find some links to Belgian case studies on ecotoxicology in pelagic fishes.

Case studies

Case study 1:Effects of xenoestrogens in eels[5]

References

  1. ↑ ↑ Kennish, M. J. (1996): Practical Handbook of Estuarine and Marine Pollution, CRC Press 524 pp
  2. ↑ 2.0 2.1 Fishes in Estuaries: M. Elliott, K.L. Hemingway (Eds.); Blackwell Science, Oxford, 636 pp
  3. ↑ Clark, R,B., 1999. Marine pollution. Oxford University press, Fourth edition, pp 161
  4. ↑ Sinderman, C.J. 2006. Coastal Pollution: Effects on Living Resources and Humans. CRC Press, Boca Raton, FL. 280 pp
  5. ↑ 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


The main author of this article is Daphnis De Pooter
Please note that others may also have edited the contents of this article.
Citation: Daphnis De Pooter (2024): Pollution and pelagic fish. Available from http://www.coastalwiki.org/wiki/Pollution_and_pelagic_fish [accessed on 21-11-2024]
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