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  • V. Laptikhovsky
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • C. Barrett
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • C. Firmin
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • P. Hollyman
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • A. Lawler
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • R. Masefield
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • R. McIntyre
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • D. Palmer
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • M. Soeffker
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
  • M. Parker-Humphreys
    Centre for the Environment, Fisheries and Aquaculture Science (Cefas)
Analysis of simultaneously occurring live molluscs and empty shells of the whelk Buccinum undatum indicated similar abundance on the seabed making possible the estimation of recent natural mortality. Nearly all empty shells were occupied by hermit crabs Pagurus bernhardus and most of the remainder by Pagurus prideaux. P. bernhardus is highly selective for robust whelk shells, whereas anemone-protected P. prideaux use a range of smaller and thin-walled shells. Application of age size keys based on age reading of opercula surfaces permitted a tentative estimate of natural mortality of M = 1.34 on trap fishing grounds for brown crab in the southwest North Sea (whelks aged 4-7 years) and M = 0.85 and M = 0.63 for the fishing grounds on the Western Waters (whelks aged 4-7 years and 4-9 years respectively). Estimates of total mortality (Z), based on size-frequencies of live whelks, were Z = 1.35 (North Sea) and Z = 1.46 and 1.23 (Western Waters, aged 4-7 years and 4-9 years). Estimates of M for the North Sea might be biased by differences in trap selectivity between hermit crabs and live whelks. This is a novel approach that might be developed for whelk fisheries assessment and management, particularly using better age determination techniques.

Keywords

  • Age, Buccinum, Hermit crab, Mortality, Whelk
Original languageEnglish
Pages (from-to)146-154
Number of pages9
JournalFisheries Research
Volume183
Early online date14 Jun 2016
DOIs
Publication statusPublished - 1 Nov 2016
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