Fishing and environment drive spatial heterogeneity in Celtic Sea fish community size structure

Samuel Shephard*, Hans D. Gerritsen, Michel J. Kaiser, Holly S. Truszkowska, David G. Reid

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Citations (Scopus)


The Large Fish Indicator (LFI) is a univariate size-based indicator of fish community state that has been selected to support the OSPAR fish community Ecological Quality Objective (EcoQO). To operate this EcoQO, a survey-based LFI for each OSPAR region needs to be developed. However, fish communities in these regions are spatially heterogeneous, and there is evidence of within-region spatial variation in the LFI that could confound an overall indicator series. For Celtic Sea trawl-survey sites, spline correlograms indicate positive spatial autocorrelation at a similar range (∼40 km) for the LFI and for fishing effort (h year -1) from vessel monitoring systems. Statistical models reveal a strong negative effect on annual LFI by site of fishing effort within a radius of 40 km. There was a weak effect of fishing within 20 km and no effect at 10 km. LFI also varied significantly with substratum and with local fish community composition identified by a resemblance matrix derived from the survey data. Finally, there was a weak effect of survey year on LFI. Spatial stratification of LFI calculations may be necessary when developing size-based indicators for OSPAR or Marine Strategy Framework Directive regions.

Original languageEnglish
Pages (from-to)2106-2113
Number of pages8
JournalICES Journal of Marine Science
Issue number10
Publication statusPublished - 1 Nov 2011


  • Ecological Quality Objective
  • ecosystem approach to fisheries management
  • Large Fish Indicator
  • marine protected areas
  • VMS

ASJC Scopus subject areas

  • Oceanography
  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology


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