Danish seine

Danish seine


Location of effort with Danish seine in 2011 (sets), dark areas indicate highest effort.

Source: The Marine Research insittute


Danish seine catch (t) by species

Source: Statistics Iceland, weight reports


Danish seine catch (t) by month

Source: Statistics Iceland, weight reports

Danish seine has been described as the poor man´s trawl. In appearance, it resembles a trawl with its wings, belly, and codend. It is operated quite differently, though, particularly as trawl doors (otter boards) are not used to keep the Danish seine open. The Danish seine is operated with a set of warps (towing-lines, drag-lines), one on each side, usually kept on large drums. The procedure of Danish seining (fly dragging) is first to set out the end of a warp on a buoy, usually the starboard warp. While the warp is set out, the boat sails in a half circle. The wing of the seine is then set out, followed by the net bag and the other wing, followed by the backboard warp when the boat heads back to the buoy. The track of the boat during this procedure forms either a circular, pear shaped, or triangular pattern. Once the buoy has been taken aboard, the towing lines made equal and fastened, the boat starts to pull the gear at a certain speed. During towing the warps are gradually pulled together, herding the fish in front of the seine. As the warps are pulled together the seine moves over the bottom, capturing the herded fish. Once the warps have come together, they are hauled in on the warping drums and the seine is taken aboard using a power block.

The Danish seine has certain disadvantages compared to trawls. It cannot work on such rough grounds as otter trawls, it demands relatively calm weathers and low currents, it is difficult to use during the night or in fog and the workload of the fishers is higher. Finally, it demands better navigational skills, since when it is set out it cannot be moved to another ground except by hauling it in first. The advantages of the Danish seine are, however, that it does not need much power to operate (low fuel consumption per catch), it is much cheaper and less bulky than a trawl and can, therefore, be used on much smaller boats. If good navigational equipment is available and the grounds are well known, the seine can be used very efficiently, for example on very rough grounds interspersed with small patches of good grounds; trawlers cannot operate there but Danish seiners can.  Finally, the tows are quite efficient in herding the fish toward the codend, especially flatfish. 

Danish seine is used chiefly to target flatfishes but also to catch large quantities of cod and haddock. About 40% of Icelandic flatfish landings are caught by Danish seine, including almost all of the dab, long rough dab and witch flounder catch and about two thirds of the plaice catch. It is used in the fisheries all around Iceland, but the bulk of the effort is southwest and west of the country. It is mostly used in shallow waters at depths of 40-60 m. Minimum mesh size for Danish seine is 135-155 mm depending on fishing areas, but in the witch flounder fisheries 120 mm mesh is allowed subject to a selectivity device also being used. The boats using Danish seines are similar in size to longliners and gillnetters. In fact many boats switch between gear types seasonally.

The Danish seine was invented in Denmark as the name implies. Although Iceland was under the Danish crown until 1944 the Danes themselves did not fish much in Icelandic waters. Almost the only exception was some fisheries with Danish seines just before the 20th century. There were considerable fisheries by Icelanders with Danish seine from the early 1930´s until 1951. The Danish seine has always been a controversial fishing gear in Icelandic waters, therefore Danish seiners had to obey the same rules as trawlers, and they were not allowed to operate within the EEZ when it was extended to 4 miles off the coast in 1952 and to 12 miles in 1958.  This meant that there were virtually no Danish seine fisheries during those times since it is a shallow water gear. The trawlers, however, could still operate in deeper water areas. By 1960 Danish seines were again allowed to some formerly restricted areas and have been operating in Icelandic waters ever since.

References and further information

References: (Gunnarsson et al. 1998), (Eiríksson 2008), (Þór 2005)

For full citation and further information on fishing gear see this page.

Hörður Sævaldsson / Hreiðar Þór Valtýsson University of Akureyri