Fish Guidance Systems

Cod and haddock could migrate from Scotland’s west coast

Researchers are predicting that an increase in sea temperatures could cause cod, herring and haddock to migrate out of west Scotland’s ecosystem, most likely to colder waters further north. The findings suggest the species are already reaching the edge of their temperature tolerance range.

Cod, herring and haddock are commercially important species to Scotland, but scientists at the Scottish Association for Marine Science (SAMS) predict the cold water species will disappear from the west coast by 2100.

Lead author Dr Natalie Serpetti, a marine ecologist at SAMS said: “These results highlight the importance of considering environmental change, as well as fishing quotas, to achieve sustainable fisheries management at an ecosystem level. We initially tested the impact of current advised fishing quotas, along with predator/prey interactions, within the ecosystem.

Our results showed that a warmer climate could jeopardise sustainable fishery management. The rising temperature showed strong negative impact on cold water species such as grey seals, cod, haddock and herring, which all declined by 2100 under the worst-case climate warming scenario”.

The report concludes that even under the best case climate change scenario, cod and herring stocks off Scotland’s west coast were predicted to collapse.

Dr Serpetti’s research has updated an existing marine model of the west coast of Scotland ecosystem, situated in the north-east Atlantic from the coastline to the edge of the continental shelf. Her study looked at how rising temperatures would affect 41 groups of species, from top predators such as whales and seals to many fish species and animals such as crabs and snails living on the sea floor.

As a part of the Marine Ecosystem Research Programme, funded by the Natural Environment Research Council and the Department for Environment, Food and Rural Affairs (DEFRA).

Commenting on the findings of the research, the Scottish government said it recognized that climate change was a ‘major threat’ to Scotland’s marine ecosystem and was following scientific advice to support a sustainable fishing industry.

Photo: Hans-Petter Fjeld