Cod, herring and haddock may vanish from Scotland’s west coast waters by the turn of the century because of global warming, a new study has claimed.
Researchers at the Scottish Association for Marine Science (SAMS) near Oban, Scotland, have predicted that by 2100, commercially important species could migrate out from the ecosystem, most likely to colder waters further north, in response to rising sea temperatures.
According to their findings, published in the journal “Scientific Reports,” cod and herring off Scotland’s west coast are already nearing the edge of their temperature tolerance range and over coming decades these species will gradually be replaced by more abundant communities of saithe, hake and whiting. Indeed, from 1985 to 2013 the population of saithe and hake off the Scottish west coast increased four-fold.
The paper’s lead author Dr. Natalia Serpetti, a marine ecologist at SAMS, said the results highlight the importance of considering environmental change, as well as fishing quotas, to achieve sustainable fisheries management at an ecosystem level.
The research initially tested the impact of current advised fishing quotas, along with predator/prey interactions, within the ecosystem. Cod, whiting and herring stocks, that historically showed declining trends due to high fisheries exploitation and predation, recovered under a sustainable fishery management. However, subsequent testing of the impact of rising temperature under Intergovernmental Panel on Climate Change (IPCC) climate change scenarios, while keeping fishing rates consistent with current advised maximum sustainable yields (MSY), found that there would be a collapse of coldwater species stocks.
Results showed that warmer climate could jeopardise sustainable fishery management: rising temperature showed strong negative impact on coldwater species such as grey seals, cod, haddock and herring, which all declined by 2100 under the worst case climate warming scenario, said Serpetti.
Even under the best-case climate change scenario, cod and herring stocks were predicted to collapse off Scotland’s west coast, she said.
Dr Serpetti’s research updated an existing marine model of the west coast of Scotland ecosystem, situated in the northeast Atlantic from the coastline to the edge of the continental shelf.
The research is part of the Marine Ecosystem Research Programme (MERP), funded by the Natural Environment Research Council (NERC) and the Department for Environment, Food and Rural Affairs (DEFRA).
