The Influence of Climate Change on North Atlantic Fish Stocks

Background and objectives

Fish stock management in the North Atlantic uses a variety of quantitative methods to track short-term changes in fish populations, however, the chronic over-exploitation of many fish resources demands urgent reduction in fishing pressure and a strategic approach based on an understanding of likely population dynamics on a decadal or longer time scale. Fish populations are heavily influenced by ocean climate. The effect of environmental conditions on fish population biology is crucial in defining the constraints under which fisheries may safely operate in the long term. For effective management it is necessary to be able to partition the variability in fish populations into environmental and fisheries effects.

A Symposium is timely because of growing concern about climate change, greater understanding of the role and behaviour of the North Atlantic ocean climate and increasing knowledge of the processes by which environmental conditions affect fish at the individual and population level. There have been substantial trends in ocean climate in recent decades, which have affected the major fish stocks in the North Atlantic. Future changes in the atmospheric and oceanic climate may cause changes in the circulation pattern, which will not necessarily lead to a warmer state.

Earlier meetings, one nearly a decade ago (ICES Cod and Climate Change Symposium, Reykjavik, 1993) and one over 50 years ago (ICES Special Scientific Meeting on Climatic Changes, Bergen, 1948) serve as a background against which our recent progress can be measured. In his Preface to the earlier meeting Gunnar Rollefsen said "The causes of fluctuations in the behaviour, occurrence and abundance of fish stocks have been attributed to widely different conditions in nature, and practically no progress has been made on some of these problems for a very long time". The challenge is to show that this is no longer true.

The main objective of the Symposium is to present current knowledge of climate impact on fish stocks and how this may be used in fisheries advice and management.