Fisheries and climate change

On a global scale, models available today expect very significant modifications of primary ocean production, which is the source of the majority of food webs. Global ocean productivity should increase in Polar Regions and drastically reduce in inter-tropical areas, which will affect fisheries. In the Pole regions, fishing operations have increased by 30 to 70%, which favours countries such as Norway, Iceland, Russia or the State of Alaska. On the contrary, in inter-tropical areas fishing operations have reduced by 10 to 40%, which has significant repercussions for near countries, highly dependent on fisheries, such as Peru, Angola, Bangladesh, India, Vietnam or Indonesia. Predictions for Africa are rather uncertain; however several scientific studies expect an actual fisheries crisis, which will increase political and economic North-South inequalities. The impacts in Europe should be relatively limited, slightly positive for the northern countries and negative for the southern countries.

In response to modifications of ocean life conditions, models predict a displacement of most of the exploited species towards the Polar Regions. By 2050, these displacements will be estimated in hundreds of kilometres. This change should favour short life span species, more abundant in tropical waters, with still barely identified impacts on ecosystems. Consequently, captured species partially will not be the same at a global level. It is the case in particular in temperate regions, where the presence of tropical species is going to increase, while other European fish species will move towards the North. For instance, this is the case for the cod, whose population in the North Sea is already declining while its population in the Barents Sea further North is increasing.

Fishers will have to adapt to climate change impacts on fish stocks and their geographical distribution, by changing their modes of exploitation, sometimes ships, calendars and fishing areas. Public policies in management, control and governance will also need some redesigning to avoid reconsidering all efforts undertaken to resupply fish stocks for over several decades. For example, the cod stock in the Gulf of Maine has recently dropped because fish quotas had been determined without taking global warming into consideration. Consequently, it is important to learn how to constantly evolve, and this adaptation has a cost and will not happen without difficulty.

Limiting CO2 emissions is a major issue, not only to mitigate current changes but also to slow them down and give ecosystems a (slight?) chance to adapt. On the contrary, if changes occur too quickly, the implementation of all adaptation processes by humans might be more difficult or even inefficient for them and the ecosystem. Chaotic situations or extreme crisis situations are expected, in particular in the field of fisheries.