Cross-Frontal Exchange and Scotian Shelf Cross-over Workshops

10-12 October, 2000

Holiday Inn, Falmouth, Massachusetts



Cross-Frontal Exchange

Presentations Discussion Topics Upcoming North Sea Study (LIFECO) (St. John)

Scotian Shelf Cross-over

Presentations Discussion Questions Synthesis Topics Appendix


LInking hydrographic Frontal activity and ECOsystem dynamics in the North Sea & Skagerrak: Impact on fish stock recruitment.


EU funded Project:     LIFECO QLRT-1999-30183.

Start Date:     December 2000

End date:       November 2003

Scientific Co-ordinator:     Mike St. John, DIFRES

Administrative Co-ordinator:     Helge Abildhauge Thomsen, DIFRES

International Partners:

1)   DIFRES:  Danish Institute for Fisheries Research

2)   IMF Kiel:   Institut für Meereskunde an der Universität Kiel

3)   CEFAS:   Centre for Environment, Fisheries and Aquaculture Science, Lowestoft

4)   University of Hamburg

5)   University of Bergen, Department of Geography

6)   IOW:   Institut für Ostseeforschung, Warnemunde

7)   IMR:   Institute of Marine Research Bergen

The principle objective of this program is to resolve the importance of hydrographic fronts (h/U3 and shelf break) and their variability for recruitment success of North Sea commercial fish stocks. Thereby, the program addresses the effects of a key hydrographic process on the dynamics of the ecosystem in a holistic manner rather than following a single species approach. The approach employed is mechanistic, resolving links and key processes, a strategy, which is necessary to understand the effects of environmental warming on the ecosystem. Particularly the latter process has been suggested to alter food web structure and ecosystem function. This approach will make more reliable the management of fish stocks in the region by the identification of a climatically driven process influencing ecosystem dynamics and hereby influencing recruitment success. This utilisation of key environmental processes in the advancement of recruitment models is an approach which has been shown to increase the predictive power of stock recruitment relationships in other systems (e.g. Baltic Sea cod; EU funded Baltic CORE program AIR2-CT-1226; Bengula anchovy). Reliable stock recruitment relationships integrating important environmental processes and species interactions are a pre-requisites for sound medium to long term projections of stock developments and thus for long-term fisheries management.

Literature on types of fronts, physical processes causing their variability as well as their influence on biological processes is exhaustive with implications for trophic levels from autotrophs to marine mammals. For example, frontal processes have been linked to variations in the distribution, condition and growth of the critical early life history stages of a number of key fish species globally. An occurrence, which makes these processes a prime candidate for modifying recruitment success of commercial fish stocks.

Typically, studies in frontal regions have had a limited physical scope as well as dealing primarily with the distribution of a limited number of lower trophic levels. The goal of the proposed project will be to investigate and to explain the linkage between climatic processes, frontal manifestation and ecosystem dynamics in order to provide scientific information to develop an environmentally sensitive management strategy of fish stocks. Furthermore, the resolution of the role of frontal regions as unique ecological enclaves will allow the development of management strategies based on environmentally distinct and sensitive regions. Hydrographic fronts have also been identified to influence the distribution of fish species. Hence the potential exists for variations in predator prey interactions between all life stages of commercial fish stocks and their prey based on overlap in their distributions and increased abundance. Studying prey selection processes and prey preferences will allow an enhanced modelling of prey suitability and by this contribute to a more realistic multi-species fish stock assessment in the North Sea. The proposed program will also contribute to a more reliable assessment of the state of the fish stocks in the North Sea. It will do so by resolving the effects of hydrographic processes on fish distributions as shown for other systems (e.g. Baltic Sea) and thus, allowing assessments based on realised habits rather than assuming a homogenous distribution.

The ecosystem approach required to address the primary goals of this program necessitates the utilisation and integration of a multidisciplinary research strategy. Hence, the program has been divided into 9 workpackages to be performed by 7 partners. The first two workpackages consist of the development and application of simulation techniques allowing:
     --   identification of key climatic processes influencing frontal manifestation,
     --   development of long term indices of frontal manifestation,
     --   resolution of the effects of frontal processes on the production and aggregation of lower trophic levels

The third workpackage consists of the assemblage and application of remote sensing data to ground truth the modelling components and develop real time indices of frontal occurrence. The next three workpackages are concerned with in situ measurement of organism distribution and trophodynamics relative to frontal processes. These workpackages are designed to resolve the pathways by which frontal processes act on recruitment success of commercially important fish species. The next two workpackages involve the development of a common database for utilisation by all participants to resolve distributional patterns using GIS data analysis and visualisation techniques. These workpackages are designed to allow the statistical examination of distributional patterns of fish species relative to frontal occurrence.

The final component is the synthesis workpackage where we will:
     a)  examine the effects of climatic processes and their variability on the dynamics of North Sea commercial fish population dynamics and develop environmentally sensitive recruitment models, (should we here not tell which one, as we will definitely not cover all exploited species)
     b)  resolve the key regimes influencing ecosystem dynamics, distributional patterns and recruitment success. The successful completion of this activity will identify potential ecological reserves for the development of area specific management strategies.
     c)  identify the necessity to adapt surveys assessing commercial fish stock abundance to address variations in abundance relative to hydrographic features,
     d)  evaluate if prey suitability coefficients utilised in existing multi-species models of North Sea fish stocks (MSFOR MSVPA) are appropriate considering a heterogeneous distribution of prey organisms due to hydrographic features and develop alternative approaches.