Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.540545
Title: Growth investment and distribution of the squid Loligo Formeshii (Caphalopoda: Longinidae) in Northeast Atlantic waters
Author: Smith, Jennifer Marie
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2011
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Abstract:
Generalised additive models (GAMs) were used on data for L. forbesii in northeast Atlantic waters to analyse patterns of reproductive and somatic investment.  Geographic variation in the relationships, seen between Scottish males and samples from other study areas, is hypothesised to be largely attributable to local differences in environmental conditions and demonstrates that L. forbesii growth and maturation is variable in response to both intrinsic and extrinsic factors.  GAMs were also applied to trawl survey data to relate squid with ecogeographic variables in order to identify the variability of the habitat preferences of L. forbesii in UK waters.  Favourable values for depth, SST, salinity and sediment composition were identified and related to known biological characteristics.  Results suggest that habitat preferences may vary from season to season, but are rather consistent across different life cycle stages of the population.  Knowledge gained could be used by fishers for more effective species targeting, and by managers as a tool to identify spawning grounds for potential protection.  Finally, the recent history of the directed squid fishery in the Moray Firth was reviewed using both fishers’ knowledge and fishery statistics.  Peaks in landings and CPUE were experienced during 2003-2005, with a marked decrease in both values in 2006.  Fishers reported egg presence during summer months, providing new evidence of summer breeding in this population.  Ideas are presented from the fishers’ viewpoints and from a research-based fishery perspective on possible drivers behind the variability in catch, as well as preferred options for future regulatory measures.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.540545  DOI: Not available
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