Mapping spatial variation in demersal fish species diversity and composition in the North Sea: accounting for species- and size-related catchability in survey trawls

H.M. Fraser, S.P.R. Greenstreet, R.J. Fryer, G.J. Piet

Research output: Contribution to journalArticleAcademicpeer-review

25 Citations (Scopus)

Abstract

The paper maps spatial patterns of groundfish species diversity. It considers how the catchability of different fish species in two different types of bottom trawls, the IBTS GOV and the 8-m beam trawl, influences the estimates of species diversity. Maps of groundfish species diversity derived from these two survey trawls are compared to determine the extent to which the maps of spatial variation in groundfish species diversity are influenced by gear type. Catchability-at-length coefficients were applied to the IBTS data to raise the observed catches to estimates of "actual" numbers of fish present in the path of the trawl, which are then used to produce maps of "actual" species diversity across the North Sea. Finally, these raised maps of "actual" groundfish species diversity are shown to be more explainable based on physical environmental parameters such as depth. We suggest that species diversity maps that take account of catchability provide more reliable information on which to base management decisions than "gear-biased" views. The implications for management are discussed, with particular emphasis on using closed areas to conserve marine biodiversity
Original languageEnglish
Pages (from-to)531-538
JournalICES Journal of Marine Science
Volume65
Issue number4
DOIs
Publication statusPublished - 2008

    Fingerprint

Keywords

  • atlantic shelf seas
  • marine protected areas
  • community structure
  • long-term
  • richness
  • patterns
  • reserves
  • trends
  • productivity
  • evenness

Cite this