ecological effects of electrofishing for ensis spp. in scotland. fiona murray 1,3, phil copland 2,...
TRANSCRIPT
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Ecological effects of electrofishing for Ensis spp.
in Scotland.Fiona Murray1,3, Phil Copland2, Phil Boulcott2, Mike
Robertson2 and Nick Bailey2
1 Razorclam Fishermen’s Forum. 2 Marine Scotland Science. 3 Present address Heriot-Watt University
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Overview• Previous razor clam study in Scotland
• Aim of this project
• Sea trials
• Tanks trials
• Conclusions and implications
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Electrofishing• https://www.youtube.com/watch?v=Z02KhkOgfVQ
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Aims of this project: Sea Trials
• Record recovery rates of Ensis spp. • Identify non-target species which may be affected
by Ensis electrofishing
• Record the recovery of non-target species
• Determine if electrofishing may cause mortalities in sandeels
• Observe the impact of the electric rig on the seabed
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• Determine the properties of the electric field generated by electrofishing
• Record the behavioural response to, and recovery from exposure to, an electric field in E. siliqua and 3 non target species
• Monitor the short term survival of E. siliqua and 3 non target species following exposure to an electric field
Aims of this project: Tank Trials
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Ensis siliqua• https://www.youtube.com/watch?v=o1gcuYmPK6
w
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Conclusions• Electrofishing (using this system) is a potentially
low impact method of harvesting razor clams.
• The impact on the seabed is minimal in comparison to conventional dredge and trawl fisheries.
• Immediate effects on non-target species are non-lethal and effects on invertebrate behaviour are short term.
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Suggested next steps• Initial stock surveys – ideally while derogation is
sought• Surveys by chartered commercial vessels using
electrofishing technology linked to quantitative camera based system. Candidates for IFG coordination with industry input to design?
• Assuming derogation granted – allow commercial fishery based on initial survey findings. Vessels participate in data gathering
• Reassess stocks with knowledge provided by fishery and survey
• Adjust scale of fisheries as required and set catch opportunities