. Conservation of diversity in an exploited species: spatio - temporal variation in the genetics of herring (Clupea harengus) in the North Sea and adjacent areas

Acronym: HERGEN

Funding agency: European Union (EU QLRT-2000-1270)

Project duration: 36 months (01/02-12/04)

Objectives: The project's overall goal is to provide guidelines for the conservation and management of biodiversity of Atlantic herring in the North Sea and adjoining waters by identifying its genetic population structure, and by quantifying relative stock contributions to the fishery.

Atlantic herring (Clupea harengus) has been the subject of much of the fundamental work on marine fish population structure, not only because of its economic and cultural importance, but also because of its heterogeneity in life-history, morphology and behaviour. However, there is still no consensus on how herring populations are structured, particularly in the North Sea, where several hypotheses, with or without sub-stocks (demes), have been proposed. Nevertheless, North Sea herring in ICES divisions IV & VIId are assessed and managed as a single stock. The assessment and management situation is further complicated by potential mixing with adjacent putative shelf stocks (West of Scotland, Division VIaN; Western Baltic, Division IIIa & IIIc). In 2000 the quota for herring in the study area was 387,000 t giving an annual value of about 100 million ECU at first sale.

The misidentification of population structure within and among stock complexes can lead to the overexploitation of component populations and, consequently, to the erosion of genetic resources by depleting spawning components even when the fishery is tightly regulated and controlled. This problem is exacerbated in stock complexes such as North Sea herring, where demographically diverse, locally adapted subpopulations that vary in their migratory tendencies intermingle seasonally, yet are managed spatially and temporally as a panmictic unit. Such concerns have, for example, led to requests to assess and manage one of the four demes in the North Sea stock, the Downs herring, separately. Knowledge of the demography of stock components is also essential in light of proposals for area closures in the North Sea.

There is, therefore, a need to provide information on stock structure in order to decide which population units should be assessed and managed individually. Additionally, a comprehensive method for differentiating between the members of these populations both in surveys and samples from the fisheries is essential, as such information may make it possible to target fishing effort primarily at more productive stocks while protecting those less productive from overexploitation. Hypervariable DNA markers (microsatellites) allow the examination of population structure in high dispersal marine species at geographic scales that are fine enough to be relevant for management purposes. We aim to use these advanced techniques to identify the stock structure of herring in the North Sea and adjacent areas. We will then examine the implications for assessment and management of the enhanced demographic stock differentiation.

Visit the project's webpage for more information: www.hull.ac.uk/hergen


Participating institutions:

entered by (Date)
Christopher Zimmermann (20-03-02)