May Organic Pollutants Affect Fish Populations in the North Sea?

Abstract

The North Sea is a highly productive area with large fish populations that have been extensively harvested over the past century. North Sea fisheries remain important to the surrounding countries despite declining fish stocks over the past decades. The main reason for declining fish stocks is nearly certainly overfishing, but other environmental pressures also affect fish populations, such as eutrophication, climate change, and exposure to metals and organic pollutants, including polyaromatic hydrocat bons (PAHs), alkylphenols, and organochlorine compounds. There are three main sources of organic pollutants in the North Sea: atmospheric, land-based sources, and inputs from offshore gas and oil installations. All three sources contribute to elevated concentrations of organic pollutants in the North Sea compared to the Norwegian Sea. There is evidence that chlorinated organic contaminants were present in sufficiently high concentrations in the southern North Sea two decades ago, to alter embryonal development in fish. The results from extensive, long-term monitoring programs show that some diseases decreased whereas other increased in the southern North Sea and that, among other factors, contaminants may play a role in the temporal changes recorded in disease prevalence. Recent studies demonstrated that components in offshore effluents may affect fish reproduction and that tissues of fish near oil rigs are structurally different to tissues of fish from reference areas. Data on effluents from offshore activities have recently become available through an international workshop (BECPELAG) and follow-up studies.

The work by the BECPELAG steering group and participants is acknowledged, as are the contributions from crews and funding agencies in the contributing countries. Funding for the BECPELAG workshop was partly provided by the Research Council of Norway and Norwegian oil companies as part of annual monitoring programs. The Research Council of Norway and the Association of Norwegian Oil Producers (OLF) funded the regional monitoring programme on PAH levels and effects (RCN project 152231/720). The German EFFSTAT project (03F0264A) was supported by the Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie (BMBF). The review on biological effects methods used in North Sea countries was compiled by the ICES Working Group of Biological Effects of Contaminants (WGBEC) at their 2004 meeting in Oostend. The contributions from our colleagues in that group are gratefully acknowledged.

Notes

*ICES Workshop on Biological Effects of Contaminants in Pelagic Ecosystems (2000–2002).

*Oslo and Paris Commissions.

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