Changes in aquatic ecosystems directly affect humans by altering livelihood, cultural identity and sense of self, and seafood provision, quality and safety. The state of marine fishery resources has continued to decline, with the proportion of fish stocks at biologically unsustainable levels of exploitation increasing from 10% in 1974 to 34.2% in 2017 . There is medium confidence that fisheries production declines in different world regions can be partly attributed to climate change, along with overfishing and other socioeconomic factors. It has been estimated that, from 1930 to 2010, the amount of fish that can be sustainably harvested from several marine fish populations has decreased by 4.1% globally due to ocean warming, with some regions , experiencing losses of 15-35% . There is regional variation such as redistribution of fishing grounds, due to climate-induced fish species migrations . In Tanzania, for example, most small-scale fishers  have reported shifting fishing grounds from nearshore to offshore areas during the last decade, due to perceived combined effects of overfishing and environmental impacts . Observed impacts in some inland aquatic systems indicate substantial productivity reductions . For example, sustained warming in Lake Tanganyika during the last ~150 years has affected the biological productivity by strengthening
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report