Rising ocean temperatures cause cool water copepod assemblages to move northward and be replaced by warm water copepods with lower biomass. This shift eliminates the large copepods required for Atlantic cod diets, causing their recruitment to plummet.
Scientific models project that global fish community biomass could decrease by as much as 30% by 2100. Global ocean fish catch is expected to decline by 6 percent over the same period while tropical zones face an even steeper drop of 11 percent.
Low-lying countries like the Maldives and Tuvalu are particularly vulnerable due to rising sea levels threatening entire communities. Nations such as Bangladesh, Cambodia, Gambia, Ghana, Sierra Leone or Sri Lanka depend on fish for more than 50% of protein intake making them highly susceptible to production decreases.
Over-fished populations possess less size, genetic diversity, and age which makes them more vulnerable to environmental stress from climate change. Studies show that destructive fishing practices cause fisheries to collapse or suffer significant impacts where they have not yet collapsed.
A 2025 systematic review reported that 67.7% of documented responses were short-term coping strategies. Only 32.3% represented longer-term adaptive strategies for small-scale marine fisheries despite support from agencies like the World Bank and Food and Agriculture Organization.