Gear trials in Skagerrak A new pelagic grid SLU Aqua Joakim Hjelm, - - PowerPoint PPT Presentation

Swedish University of Agricultural Sciences www.slu.se

Gear trials in Skagerrak

A “new” pelagic grid SLU Aqua

Joakim Hjelm, Andreas Sundelöf, Daniel Velentinsson, Hans Nilsson, Mikael Ovegård, Anders Wernbo

SPFPO, Carmona GG 330

Swedish University of Agricultural Sciences www.slu.se

The problem

• During Q3 saithe is pelagic in

Skagerrak

• Hence, there is bycatch of saithe in

herring fishery (Aug-Sept)

• No specific quota for saithe in the

Swedish pelagic system

Swedish University of Agricultural Sciences www.slu.se

Conditions

• The SPFPO contacted SLU
• Grids in pelagic gear have been

used in blue whiting and Norway pout fisheries in Faeroe Islands and Norway

• Not extensively tested or

evaluated in other fisheries

• Gear trials supported by

Swedish Agency for Marine and Water Management (SWaM) and the Ministry.

Swedish University of Agricultural Sciences www.slu.se

Gear trials

• Not possible to have a double set of trawls
• Camera used for observations/quantitative

evaluation

• 4 weeks of experimental work in Aug-Sept

2015 on-board GG330 Carmona

The light and camera

Swedish University of Agricultural Sciences www.slu.se

A possible solution

Schematic presentation

grid with a protective sheet

Codend Grid Protective sheet Front of trawl Light and camera

Swedish University of Agricultural Sciences www.slu.se

Setting up the Saithe grid

Swedish University of Agricultural Sciences www.slu.se

Initial trials

• Cameras; finding the angle and

position of cameras for good footage

• Grid set up; angle and position

Objectives

• Minimize saithe bycatch
• Minimize loss of herring

Swedish University of Agricultural Sciences www.slu.se

Results - general

Swedish University of Agricultural Sciences www.slu.se

Haul # Herring Catch (t) Loss of Herring (t) Herring loss % Saithe catch (t) Catch of Saith (t) calculated Saithe bycatch (%) Film Film Film 7 65 1.74 2.7 0.37 7.32 5.0 12 70 3.68 5.3 0.24 3.71 6.5 13 36 5.39 15.0 0.22 2.79 7.9 14 40 2.96 7.4 0.20 2.55 7.8 15 30 2.88 9.6 0.16 3.90 4.1

Results according to

• bjectives

Swedish University of Agricultural Sciences www.slu.se

Codend Grid Front of trawl Light and camera

Schematic presentation

grid without a protective sheet

Swedish University of Agricultural Sciences www.slu.se

Swedish University of Agricultural Sciences www.slu.se

Implications of a saithe grid

• Few vessels fish during day-time

during Q3

– i.e. substantial unwanted catch

• Grid reduces unwanted catch of saithe

with 92-96%

– 25-75 kg Saithe/h during trials observed

• Look into fish behaviour inside the

trawl

• How to set up the grid (new material),

position and angle

Way forward