Report of the

U.S. GLOBEC Georges Bank

Science Meeting

18 - 20 November 2003, Rhode Island

 


Cover Page

Acknowledgements

Introduction

Narrative

Presentation Abstracts

Poster Presentations

Appendix I: Agenda

Appendix II: List of Participants

Appendix III: List of Planned Publications


Development of Multispecies Models of Fish Community Dynamics on Georges Bank

Stockhausen, W.1,2 and M. Fogarty1

1Northeast Fisheries Science Center, NOAA Fisheries, Woods Hole, MA 02543
2Woods Hole Oceanographic Institution, Woods Hole, MA 02543

The biomass of major nektonic species on Georges Bank has undergone dramatic changes since the 1960's under the direct and indirect effects of fishing. To characterize the effects of these changes in community structure on production at tertiary and higher levels, as well as to identify species interactions that may confound future recovery of currently depressed populations, a set of multispecies models of fish community dynamics on Georges Bank is being developed. Model parameters will be estimated using temporally-smoothed estimates of absolute species biomass based on the 40-year dataset of semi-annual bottom trawl surveys conducted by NOAA's Northeast Fisheries Science Center. Catchability coefficients used to scale the "raw" trawl survey data to estimates of absolute biomass were derived from previous studies and a new analysis of the survey data. Using these coefficients, time series of absolute biomass were calculated for nine ecologically and commercially-important species. An ARIMA-based smoothing algorithm was implemented to reduce effects of sampling variability on individual time series. Details of this process are discussed and the resulting time series of absolute biomass are presented. The multispecies production models will provide a dynamic framework complementing the static energy budget also being developed. In addition, the biomass estimates will be useful for estimating production of the nekton in the static energy budget.

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