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Pelagic Trawling for Cod, Haddock and Saithe in the Barents Sea

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Pelagic Trawling for Cod, Haddock and Saithe in the Barents Sea ... Test pelagic fishery for species typically caught in ... flatfish) Reduce fuel consumption ... – PowerPoint PPT presentation

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Title: Pelagic Trawling for Cod, Haddock and Saithe in the Barents Sea


1
(No Transcript)
2
Pelagic Trawling for Cod, Haddock and Saithe in
the Barents Sea
Shale Rosen, Terje Jörgensen and Arill
Engås Insitute of Marine Research Postboks 1870
Nordnes N-5817 Bergen Norway shale.rosen_at_imr.no
Nor-Fishing Technology Conference 2008 Trondheim,
Norway 11-12 August 2008
3
Overview
  • Glossary
  • Introduction to project, objectives
  • 1960s-1970s pelagic trawl fishery
  • Why the renewed Interest?
  • Data collection
  • Catches
  • Comparison with demersal trawl catches
  • Conclusions
  • Next steps

4
Glossary
  • Pelagic Trawl Midwater Trawl Flytetrål
  • Demersal Trawl Bottom Trawl Bunntrål

Cod Torsk Gadus morhua
Haddock Hyse Melanogrammus aeglefinus
Saithe Sei Pollachius virens
Images Northeast Fishery Science Center
www.nefsc.noaa.gov
5
Introduction to Project
  • Test pelagic fishery for species typically caught
    in demersal trawls
  • Research Topics
  • Availability of cod, haddock, saithe to pelagic
    trawls
  • Selectivity of pelagic trawls
  • Behaviour as trawl approaches and once inside
  • Development of pelagic trawl to target cod,
    haddock, saithe

6
1960s-1970s Pelagic Trawl Fishery
  • Spring fishery for cod and haddock off northern
    tip of Noway, late summer fishery for haddock
    farther offshore
  • Closed 1979 due to reports of high bycatch of
    juveniles (higher than in demersal trawls)

7
Why the Renewed Interest?
  • Impacts of demersal trawls on seabed
  • Reduce bycatch of highly demersal species (eg.
    flatfish)
  • Reduce fuel consumption
  • Sorting grids and larger mesh proven successful
    in other trawl fisheries

8
Data Collection, Net and Sensors
9
Data Collection (cont.)
  • Distance between doors and height relative to
    headrope and footrope
  • Amount of towing wire and tension
  • Catch in grid cover, cod end, and cod end cover

grid cover
10
Catch Locations and Vertical Distribution, Cod
April 2008 cruise, pelagic cod area
11
Catches in Pelagic Trawl
  • Total 175 tons

50 in just 3 hauls!
12
Length Distributions of Catch
  • Few undersized fish encountered, removed by
    sorting grid

13
Length Distributions of Catch Comparison with
Demersal Trawl
  • Larger cod captured in cod end of pelagic trawl

mean 81 cm 5 kg
mean 75 cm 4 kg
14
Comparisons With Demersal Trawls
15
Conclusions- Gear
  • Opening of 40 m by 60 m was well-sized for the
    distributions and behaviour we encountered.
  • Benthic trawl doors spread net adequately and
    made it easy to switch between pelagic and
    demersal trawls
  • 300mm liner in belly may not be necessary (at
    most 9 fish meshed per haul)

16
Conclusions- General
  • In the right conditions, pelagic trawl is a
    highly effective way of catching cod (150 tons in
    5 days)
  • Most effective during brightest daylight hours
  • Sorting grid effectively removed small gadoids
    and pelagics (herring and blue whiting)
  • Cod caught in pelagic trawl were larger than in
    demersal trawl
  • CPUE higher in pelagic trawl than demersal trawl,
    when pelagic distributions were present
  • Fuel consumption between that of single and twin
    demersal trawl
  • Not a replacement for demersal trawls, but
    pelagic trawls may increase fleets flexibility
    and reduce seabed impact for each portion of
    quota caught without using demersal trawl

17
Next Steps
  • October cruise on R/V, focused on behaviour and
    selectivity studies
  • Spring 2009 cruise on F/T, focused on use in
    commercial fishery
  • Discussions with Fisheries Directorate about
    authorizing an experimental fishery with data
    collection
  • We anticipate continued cooperation with net
    manufacturers and fishermen to refine design for
    selective and efficient pelagic trawls for gadoids

18
Acknowledgements
19
Questions?
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