During the 20th century, humans increasingly exploited the living resources of the ocean. The increase in catches was accompanied by a decrease in resources and overfishing became a widespread practice, characterized by inefficiency of the production system. In Europe, however, fishing pressure has been declining for about 15 years, and there are initial signs of recovery of exploited stocks. But to ensure sustainable fishing, it is not enough to adjust catches to the biological production of each stock. This is of particular importance given that the ecosystem approach to fisheries and the expected impacts of climate change require us to tighten up environmental requirements and rethink the concept of sustainable fisheries.
Climate change is impacting the productivity of marine ecosystems and fisheries, while demand for fish for human consumption is increasing. Fish is the main source of animal protein for one billion people and is one of the most traded renewable resources in the world. Changes in physical and chemical characteristics of seawater affect individual metabolism, species’ life cycles, predator-prey relationships, and changes in habitat. Geographic distributions of fish (migration rate towards the poles is 72.0 ± 13.5 km/decade) and ecosystem dynamics could undergo profound disruption in the coming decades, impacting fisheries globally and jeopardizing food security in many southern countries. Maintaining healthy, productive marine ecosystems is a critical issue.
Aquaculture is a booming sector, currently supplying more than half of the fish and shellfish on
world markets. Climate change will affect some aquaculture activities; however, the scale of these impacts cannot yet be quantified, given the uncertainty of global models. Adaptation of production systems is potentially feasible through actions by all stakeholders involved. Direct impacts will be related to changes in production conditions in freshwater, brackish water and marine environments. The main indirect impact is likely to be related to the dependence on an exogenous food supply for the cultivated organisms. However, the negative (inland water eutrophication, ocean acidification, etc.) and positive impacts (aquaculture activities in colder areas, better growth of farmed organisms, etc.) could balance out. Finally, impacts will vary depending on region and type of production.