Climate change threatens cod stocks – Fishupdate.com

Climate change threatens cod stocks Published:  07 May, 2007

COD stocks in the North East Atlantic, already at risk from over-fishing, are also facing a very real threat from climate change, according to a new report.

The WWF report says that the current over-fishing by UK and European fleets has led to the decline of many commercial fish stocks in the North East Atlantic and that climate change is making matters worse. Immediate measures need to be taken to give stocks a chance to rebuild and sustain themselves and reduce pressures on the ecosystem which compound the impacts of climate change, the report concludes.

According to the report, the marine climate of the North East Atlantic has been warming faster than the global average rate of change since the 1980s and British coastal waters have shown a general warming trend, with annual sea surface temperatures increasing by up to 1 degree centigrade. This is set to continue with global climate models forecasting a further warming of 0.5 to 1.0°C in seas around Britain during the 21st century. Even greater rises are predicted in areas such as the English Channel, which may warm by as much as 4°C.

The increasing sea temperatures signal an additional concern for fragile cod stocks around the British Isles. WWF says cod has been over-exploited in the North Sea since the late 1960s and stocks have been below safe biological thresholds for several years. Although over-fishing remains the main pressure on commercial fish stocks, it says it is now clear that climate change is also having a detrimental effect on over-fished cold water species by playing a part in declining recruitment – the amount of fish added to the exploitable stock each year due to growth and/or migration into the fishing area.

Recent studies have shown very poor recruitment in warm waters during the late 1990s. Stocks show a general decrease in numbers in response to warming waters and this is preventing recovery. Changes in climate affect larval growth and survival, and also act indirectly, affecting the availability of prey for juvenile fish. If levels of stock continue to decline at their current rate, WWF says, the risk of stock collapse is extremely likely, and when cod populations decline to low abundances they are even more vulnerable to the effects of climate change.

According to the report, climate change impacts must be factored in and fishing effort adjusted accordingly otherwise we face the possibility of a catastrophic stock collapse as seen in the North West Atlantic.

Emily Lewis-Brown, Marine Climate Change Officer at WWF says: “It is imperative that greenhouse gas emissions in the UK are cut by 60 to 80 per cent by 2050 with binding targets for year on year reductions of at least 3 per cent in the Government’s Climate Change Bill.”

Dr Tom Pickerell, Fisheries Policy Officer at WWF-UK said: “Climate change and continued high fishing pressure, despite the cuts made by the UK fleet, are acting together to prevent the rebuilding of our cod stocks. While urgent and immediate action is needed to mitigate against climate change in the long-term, we also need to reduce the amount of cod removed from the sea in the short-term. The most realistic way of achieving this is to stop the wasting of cod caught and thrown away in other fisheries. In the North Sea alone, reported landings in 2005 were 28,000 tonnes, and the discard was estimated to be 63,000 tonnes.

“Because cod is caught with other species we can’t simply stop catching cod alone unless we closed other profitable, and reasonably sustainable fisheries – something WWF does not wish to see.”

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