Climate change increases fish biodiversity (1/18/2008)

Closeup of a school of anchovies

At first, the fishing industry may be happy to hear the results of a climate change study by Bangor University that will be published by the scientific journal 'Global Change Biology': rising water temperatures at the bottom of the seas can lead to an increase in the diversity of fish that is found in UK waters.

Jan Geert Hiddink of Bangor University in Wales and Remment ter Hofstede of Wageningen IMARES in the Netherlands used long term scientific surveys in the North Sea and discovered that since 1985, a temperature increase of almost 1.5 degrees Celsius caused the number of bottom-dwelling fish species in the North Sea to increase by half over this period.

In the world's oceans, fish diversity generally increases from north to south. As the earth warms up, the more diverse fish communities of the south should start moving northward. Indeed, many fish species are moving into the warming North Sea from the south, while only a few species are disappearing to the north. But the area's fishermen should not cheer too quickly. Some of the new species, such as anchovies and red mullet, may be a welcome addition to trawler catches. However, most of the species that are moving in from the south are small and of little commercial value, while the species that are moving out to the north are large valuable species such as wolffish, spurdog and ling. Hiddink and ter Hofstede think similar changes are probably underway in other northern waters.

'This research will help us understand and predict what the effect of climate change on biodiversity will be. Fishery managers will have to adapt their practices to a fishery with many small species rather than a few large species', according to Bangor scientist Dr Jan Hiddink.

Increases in fish species richness depend on easy migration of fish species from the south, and higher species numbers to the south. An increase in fish biodiversity is therefore not expected in tropical regions, where no species pool is available to the south.

The article, entitled 'Climate induced increases in species richness of marine fishes', by Dr Jan Hiddink and Remment ter Hofstede is published online in the scientific journal 'Global Change Biology'.

Note: This story has been adapted from a news release issued by Bangor University

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