Climate change impacts on fish of relevance to the UK and Ireland, MCCIP Science Review 2023

KEY FACTS
What is already happening?
• Increases in warm-water fish species in UK waters continue to be
observed, along with local declines of some cold-affinity species.
• Research continues to support the hypothesis that temperature
changes are affecting fish growth and age at maturation in UK
waters.
• New experimental studies have shown that fin-fish larvae may be
sensitive to changes in ocean acidification, but different species have
shown a variety of responses.
• Several species of cephalopods have shown noticeable increases in
abundance and geographical spread in UK waters, a change
consistent with warming waters.
• Recent evidence supports the hypothesis that reproductive success in
Atlantic cod is negatively impacted at temperatures above 9.6°C.
What could happen in the future?
• Ocean temperatures are expected to continue to rise and will affect
species composition and abundances, particularly in shallower areas
such as the southern North Sea.
• Shifts in food-webs may occur due to changes in species
composition and abundances affecting predator-prey relationships.
• For important commercial species, such as cod, areas such as the
northern North Sea will remain suitable habitat throughout the
coming century but more southern areas will become less suitable.
• Such sub-regional effects will need to be taken into account in
fisheries management plans and advice, and this may require
changes in the spatial scales at which data are collected, reported and
analysed in the coming decades.