Assessment of the effect of the Swedish Grid on commercial fishing for Nephrops

Our trials assessed the effect to the nephrops catch when using the pioneering ‘Swedish Grid’ to allow unwanted cod escape the net. The grid had minimal impact on the important prawn fishery but significantly reduced by-catch helping to rebuild cod stocks in the Irish Sea.

Project aim: access any losses to the catch when using the Swedish Grid

In 2009 BIM conducted further trials in the Irish Sea on the use of this selective fishing method. We access any losses of prawns (Nephrops) and marketable fish when using the grid.

Our methods: trials with industry

Our observer was onboard the mfv ‘Matter Dei’ in Area VIIa during two, three day fishing trips.

The trials were conducted using a twin-rig catch comparison with one trawl rigged as standard and the other with a Swedish Grid.

Our observer:

  • weighed all catches of Nephrops and marketable fish during normal commercial fishing activity and
  • noted any issues with the performance and onboard handling of the grid 

 Floatation device attached to the top of the grid.

It was necessary to increase floatation at the top of the
grid to prevent it sinking into the soft mud of the Irish Sea.

A view of the Swedisn Grid in the net as it is hauled onboard. 

The Grid got blocked by crab, seaweed and other
marine debris during the trawl which may have affected the catch.

Seeing the benefits: loses to the Nephrops catch minimised

Some losses to the catch when using the grid were observed, however, adoptions made to the floatation of the gear indicated that loses could be minimised.

The use of the Swedish Grid significantly reduces by-catch of cod allowing the important prawn fishery to continue while rebuilding the Irish Sea cod stocks.

The catch of prawns with no cod 

The effectiveness of the grid is apparent in this example of
clean Nephrops from a grid trawl

Potential for further improvements: 

Adjustments to the installation of the grid could also be of benefit. 

 

Contact Us

To learn more about this project, contact:

Daniel McDonald
Direct: +353 74 9381744
mcdonald@bim.ie

Latest Work

Visit our Publications page for reports on the latest gear trials  including:

- Assessment of a 300 mm square-mesh panel in the Irish Sea Nephrops fishery, 2014 Report

- Catch comparison of Quad and Twin-rig trawls in the Celtic Sea Nephrops fishery, 2014 Report

Download our report assessing the effect of placing a Celtic Sea SMP aft of a Swedish Grid on board MFV Mater Dei in the Irish Sea Nephrops fishery in August 2013

Swedish Grid Celtic Sea Square Mesh Panel Trial 2013 (pdf 1,351Kb)