March 26, 2018 โ Current fishery targets may become unachievable as the planet warms.
A new study, led by Plymouth Marine Laboratory (PML), has found that the proportion of large fish in the North Sea may decrease as climate change unfolds, by as much as 60% in some areas. The effects of warmer waters and ocean acidification may mean proposed fisheries management targets based on fish size could be unachievable if the effects of environmental change on fish size are not considered.
Using state-of-the-art modelling and comparison with real-life surveys, the researchers demonstrated they can simulate how fish size is changing in our marine environment, under the pressures of fishing and environmental factors. This form of modelling, combining important indicators and environmental change, can help with sustainable exploitation of fished stocks by helping policy makers consider how wild populations are impacted by changing, warmer and more acidic oceans into the future.
Indicators based on fish size are widely used in the study and management of wild populations exploited by commercial fishing. The Large Fish Indicator (LFI) is one such example, determining the biomass of fish above a certain size in a community, and used to inform policy and guide the fishing industry.
While widely used, however, these types of indicators have not previously been used alongside predictions of future conditions in line with expected climate change. Fish size closely reflects the environment, and a warming world will change the conditions in which fish live. It has been suggested that rising water temperatures in the North Sea, for example, are driving down fish size in key species. By modelling North Sea fish populations alongside predicted climate change scenarios for LFI, scientists have shown how climate change may affect fish communities, and what it may mean for fisheries.