Editing Teleost (section)

=== Impact on stocks ===

[[File:Atlantic cod capture 1950 2005.png|thumb|right|Capture of Atlantic Cod 1950–2005 ([[FAO]])]]

Human activities have affected stocks of many species of teleost, through [[overfishing]],<ref name="gaiavince">{{cite web |url=http://www.bbc.com/future/story/20120920-are-we-running-out-of-fish |title=How the world's oceans could be running out of fish |author=Vince, Gaia |publisher=BBC |date=20 September 2012 |access-date=1 May 2016}}</ref> [[water pollution|pollution]] and [[global warming]]. Among many recorded instances, overfishing caused the complete collapse of the [[Atlantic cod]] population off [[Newfoundland (island)|Newfoundland]] in 1992, leading to Canada's indefinite closure of the fishery.<ref>{{cite journal |last=Kunzig |first=R. |url=http://discovermagazine.com/1995/apr/twilightofthecod489 |title=Twilight of the Cod |journal=[[Discover (magazine)|Discover]] |date=April 1995 |page=52}}</ref> Pollution, especially in rivers and along coasts, has harmed teleosts as sewage, pesticides and herbicides have entered the water. Many pollutants, such as [[heavy metals]], [[organochlorine]]s, and [[carbamate]]s interfere with teleost reproduction, often by disrupting their [[endocrine]] systems. In the [[common roach|roach]], river pollution has caused the intersex condition, in which an individual's gonads contain both cells that can make male gametes (such as [[spermatogonia]]) and cells that can make female gametes (such as [[oogonia]]). Since endocrine disruption also affects humans, teleosts are used to indicate the presence of such chemicals in water. Water pollution caused local extinction of teleost populations in many northern European lakes in the second half of the twentieth century.<ref name="WoottonSmith2014">Wootton and Smith 2014, pp. 123–125</ref>

The effects of climate change on teleosts could be powerful but are complex. For example, increased winter precipitation (rain and snow) could harm populations of freshwater fish in Norway, whereas warmer summers could increase growth of adult fish.<ref name="KernanBattarbee2011">{{cite book |last1=Kernan |first1=Martin |last2=Battarbee |first2=Richard W. |last3=Moss |first3=Brian R. |title=Climate Change Impacts on Freshwater Ecosystems |url=https://books.google.com/books?id=ZVAdx0wYvAwC&pg=PA93 |year=2011 |publisher=John Wiley & Sons |isbn=978-1-4443-9127-5|page=93}}</ref> In the oceans, teleosts may be able to cope with warming, as it is simply an extension of natural variation in climate.<ref>{{cite book |title=Fisheries Management and Climate Change in the Northeast Atlantic Ocean and the Baltic Sea |url=https://books.google.com/books?id=5IAMCXnws6cC&pg=PA48 |year=2008 |publisher=Nordic Council of Ministers |isbn=978-92-893-1777-1 |page=48}}</ref> It is uncertain how [[ocean acidification]], caused by rising carbon dioxide levels, might affect teleosts.<ref name="PlanBoard2013">{{cite book <!-- author parameter causes error with so many commas, no apparent workaround --> |author=Committee on the Review of the National Ocean Acidification Research and Monitoring Plan, Ocean Studies Board, Division on Earth and Life Studies, National Research Council |title=Review of the Federal Ocean Acidification Research and Monitoring Plan |url=https://books.google.com/books?id=7B11AgAAQBAJ&pg=PA3 |year=2013 |publisher=[[National Academies Press]] |isbn=978-0-309-30152-7 |page=3}}</ref>