Small mesh trawl
Small mesh trawl
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Location of effort with shrimp and nephrops trawl in 2008 (hours trawling). dark indicate highest effort. Source: The Marine Research Insitute
Shrimp trawl catch (t) by species Source. Statistics Iceland, weight reports
Nephrops lobster trawl catch (t) by species Source. Statistics Iceland, weight reports |
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Shrimp trawl catch (t) by month Source. Statistics Iceland, weight reports
Nephrops trawl catch (t) by month Source. Statistics Iceland, weight reports |
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Many variants of bottom trawls are used around Iceland but the most specialized are the small mesh trawls, used to catch northern shrimp and nephrops lobster. Although these are all treated here under the same heading they are in fact quite different.
In the shrimp fisheries the minimum mesh size is 45 mm in the wings and towards the square but 36 mm beyond that. Offshore shrimp trawls are usually larger than groundfish trawls, but they have a smaller mesh size and the wires leading from the trawl to the trawl doors are much shorter. Inshore shrimp trawls are, on the other hand, quite small. Trawling is slow in the shrimp fisheries and the trawl may be in the water for 10-12 hours in the deepwater fisheries. Sorting grids are obligatory in the deepwater shrimp fisheries, primarily in order to avoid a bycatch of small redfish and Greenland halibut.
In the nephrops fishery the requirements are a minimum mesh size of 135 mm in the square and 80 mm in other sections of the trawl. The lobster trawl has a groundrope (see picture on page on Bottom trawl) but not bobbins as groundfish or shrimp trawls. This means that they cannot be used on such rough grounds. However, the important gain is that the opening of the net is closer to the bottom which increases the catchability of lobster.
Shrimp trawlers did catch large amounts of other species such as cod, haddock, redfish and Greenland halibut. Sorting grids have been obligatory since 1996 and bycatch of fish species has, therefore, been substantially reduced. Sorting grids are not used by lobster trawlers, which, as a result, have large amounts of cod, redfish, haddock, monkfish and witch flounder bycatch. Boats using lobster trawl are mainly decked boats of intermediate size. The shrimpers are a much more variable fleet. Some very small decked boats fish for inshore shrimp while large trawlers fish offshore.
References and further information
References: (Gunnarsson et al. 1998), (Þór , 2005)
For full citation and further information on fishing gear see this page.
Hörður Sævaldsson / Hreiðar Þór Valtýsson University of Akureyri
