Page last updated at 19:13 GMT, Thursday, 7 May 2009 20:13 UK

Shrimp tuned to ocean temperature

By Victoria Gill
Science reporter, BBC News

Northern shrimp
Northern shrimp are sensitive to temperature changes at the seafloor

Stocks of northern shrimp, the essential ingredient in the ubiquitous prawn cocktail, could be badly affected if ocean temperatures rise.

Researchers report, in the journal Science, that shrimp eggs hatch within days of each spring phytoplankton bloom - the main food source for the larvae.

They conclude that shrimp are adapted to local temperature, which determines how long eggs take to develop.

If seas warm, as predicted, shrimp stocks could collapse, the team says.

The international team of scientists found that, throughout the north Atlantic - from Cape Cod in the US to to Svalbard in Norway - northern shrimp (Pandalus borealis) eggs hatched, on average, in time with the bloom.

This is the period when food is abundant, so the larvae have a far better chance of survival.

But to get the timing right, the shrimp must mate during exactly the right period during the previous year.

North Atlantic map
Further north, the algal bloom (green) happens later

"They don't do this on a year by year basis - deciding to mate a week later because the algal bloom will be a week later," said Peter Koeller, a researcher from the Bedford Institute of Oceanography, who led the study.

"This is on evolutionary time scales - they have adapted to local conditions."

This means it would be impossible for the shrimp to adapt to a rapid change in temperature at the seafloor, where they live.

Shrimp boats

Dr Koeller's team collected samples of shrimp daily and counted the proportion of females that were still carrying their eggs. With satellite imaging, they were able to compare the timing of the algal blooms to the release of the larvae.

Shrimp trawler
The tasty crustaceans make up 70% of a 500,000 tonne annual shrimp harvest

As Dr Koeller pointed out, an explosion in the northern shrimp population in the 1980s and 1990s was linked to a drop in sea temperatures at that time.

He said it was feasible that the opposite could happen "as the climate changes".

"As surface waters warm, this would eventually result in warmer water at the bottom, which would lead to faster development of eggs and earlier hatching," he explained.

"The larvae would be further removed from period of food abundance, which would mean poor survival rates and fewer shrimp."



Print Sponsor


SEE ALSO
Bleak forecast on fishery stocks
13 Feb 09 |  Science & Environment
'Coral lab' offers acidity insight
12 Mar 09 |  Science & Environment
Marine life faces 'acid threat'
25 Nov 08 |  Science & Environment
Rains revive prehistoric shrimp
28 Aug 08 |  South of Scotland

RELATED INTERNET LINKS
The BBC is not responsible for the content of external internet sites


FEATURES, VIEWS, ANALYSIS
Has China's housing bubble burst?
How the world's oldest clove tree defied an empire
Why Royal Ballet principal Sergei Polunin quit

BBC iD

Sign in

BBC navigation

Copyright © 2016 BBC. The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.

Americas Africa Europe Middle East South Asia Asia Pacific