Climate change and fisheries

[8] Increased risks of floods, diseases, parasites and harmful algal blooms are climate change impacts on aquaculture which can lead to losses of production and infrastructure.

[12] Furthermore, the rise in sea levels also affects other ecosystems such as mangroves and marshes, making them experience a lack of both land and hinterland for the purpose to migrate.

All this can lead to changes of ocean currents, for example a weakening of the Atlantic meridional overturning circulation (AMOC).

[7]: v The rising ocean acidity makes it more difficult for marine organisms such as shrimp, oysters, or corals to form their shells – a process known as calcification.

[20] As a result, the distribution,[21] productivity, and species composition of global fish production is changing,[22] generating complex and inter-related impacts[23] on oceans, estuaries, coral reefs, mangroves and sea grass beds that provide habitats and nursery areas for fish.

Changing rainfall patterns and water scarcity is impacting on river and lake fisheries and aquaculture production.

Diverse models predict that by 2050, the total global fish catch potential may vary by less than 10 percent depending on the trajectory of greenhouse gas emissions, but with very significant geographical variability.

Decreases in both marine and terrestrial production in almost 85 percent of coastal countries analysed are predicted, varying widely in their national capacity to adapt.

In the case of Atlantic cod located in the Baltic Sea, which are stressed close to their upper limits, this could lead to consequences related to the population's average size and growth.

[33] Increase in water temperature as a result of climate change will alter the productivity of aquatic ecosystems.

The lack of oxygen in warmer waters will possibly lead to the extinction of aquatic animals[43] Worldwide food security may not change significantly, however rural and poor populations would be disproportionately and negatively affected based on these criteria, as they lack the resources and manpower to rapidly change their infrastructure and adapt.

In Bangladesh, Cambodia, Gambia, Ghana, Sierra Leone or Sri Lanka, the dependency on fish for protein intake is over 50%.

Excess nutrients in water bodies, or eutrophication, can result in more algae and plant growth which can be harmful to humans, aquatic communities, and even birds.

[47] The change in temperature and decrease in oxygen is expected to occur too quickly for effective adaptation of affected species.

[48] Several international agencies, including the World Bank and the Food and Agriculture Organization[49] have programs to help countries and communities adapt to global warming, for example by developing policies to improve the resilience[50] of natural resources, through assessments of risk and vulnerability, by increasing awareness[51] of climate change impacts and strengthening key institutions, such as for weather forecasting and early warning systems.

[citation needed] Investment in sustainable aquaculture[54] can buffer water use in agriculture while producing food and diversifying economic activities.

Some activities generate both mitigation and adaptation benefits, for example, the restoration of mangrove forests can protect shorelines from erosion and provide breeding grounds for fish while also sequestering carbon[57].