Angry fishermen have ridiculed scientists’ claims that their staple species are shrinking because of global warming.
Experts at Aberdeen University say North Sea haddock, herring and sole are getting smaller because the water temperature is rising.
They based their findings on data collected over nearly four decades.
But last night one top skipper and the owner of an award-winning chip shop dismissed fears that the traditional fish supper would have to be downsized.
Staff at the university’s School of Biological Sciences, who led the study, said that over a 38-year period from 1970, the maximum body length of haddock, whiting, herring, Norway pout, plaice and sole decreased by as much as 29%. They say that coincided with an increase in water temperatures of between 1C-2C.
Alan Baudron, research fellow at the school, said: “We used data collated by the International Council for the Exploration of the Sea reporting the age and length of commercial fish in the North Sea.
“Our analysis showed that the majority of species examined – specifically haddock, whiting, herring, Norway pout, plaice and sole – experienced a synchronous reduction in their maximum length over the time period.
“This suggests that the one common factor they all experienced – increasing water temperatures – could have been at least partly responsible for the observed reductions in length.
“The timing of the reduction in maximum length coincided with years when water temperature in the North Sea increased.
“Our findings are consistent with current understanding of the physiology of fish. In general, fish grow more rapidly during their early life when temperatures are warmer. The consequence of rapid juvenile growth is that they become mature at a smaller length and therefore don’t grow as large as they would have in colder waters.
“Other factors, such as food availability or fishing pressure, also contribute to variability in body length. However, we showed that it is less likely that these factors could explain the synchronous change in length observed across species.”
But Jimmy Buchan, skipper of the Peterhead-registered Amity II and star of the Trawlermen TV series, described the claims as “utter rot” and urged Mr Baudron to meet fishermen.
“Claims like these fly in the face of what we fishermen see on a daily basis and make me really angry. Such claims threaten the industry and communities which it supports and must stop. I would urge him to meet with us and see for himself the size of fish we are catching, which I think have never been bigger or better.”
Calum Robertson, owner of The Bay Fish and Chips in Stonehaven, which currently holds the title of best in the UK, said: “These claims are pure tripe. We buy our fish at a certain grade, so it’s always the same size, however we have no issue with its size. Despite what people would have you believe, the portion size will not be getting smaller.”
Tara Marshall, senior lecturer at the university and co-author of the paper, said her team had access to data which fishermen did not. “We were able to look at the age of these fish, which is very important. However, one species which bucked the trend was cod and we have no idea why that is.”
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