Blue ling
Blue ling
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Blue ling Illustration: Jón Baldur Hlíðberg |
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Blue ling fishing grounds in 2008 (t/nm2), all gear combined. Dark areas indicate highest catches Source: The Marine Reacearch Institute
Blue ling catch (t) in Icelandic waters Source: ICES, Statistics Iceland
Blue ling catch (t) by month Source: Statistics Iceland, weight reports
Blue ling catch (t) by fishing gear Source: Statistics Iceland, weight reports
Blue ling biomass index in annual groundfish survey in march and catch per unit effort (CPUE) for the trawler fleet Source: The Marine Reacearch Institute
Blue ling catch (t) by type of processing Source: Statistics Iceland, processing reports
Value of exported blue ling products by main countries in 2008 (FOB million ISK) Source: Statistics Iceland |
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Scientific: Molva dipterygia. English: Blue ling. Icelandic: Blálanga, mjólanga. For more languages see the Marine Animal Dictionary.
Biology and distribution
The blue ling is a medium to large sized, very long and slender codfish. Usual size in catches is 70 to 110 cm, but the largest individual caught in Icelandic waters measured 153 cm. It is found all around Iceland, but is much rarer in the colder waters north and east of the country. It is primarily a deep water fish, found in the depth range of 130 to 1500 m but mostly at a depth of between 300 and 800 m. It is found in European waters from Murmansk and into the Mediterranean Sea. It also occurs around the Faroe Islands, and has been reported in waters off southern Greenland and on the Grand Banks, off Canada.
Blue ling feeds primarily on other fishes, but also, to a lesser extent, on benthic invertebrates. Spawning takes place in deep waters off the south and west coasts, from February to April. Growth is rather slow and the fish reach sexual maturity at the age of 9 to 11 years, measuring 75 to 90 cm. The blue ling can reach 20 years of age.
Catch and fishing methods
Blue ling catches were initiated by German boats after 1960. Icelandic catches first reached more than 1,000 tonnes in 1978 and soon after, the blue ling was almost exclusively fished by Icelandic boats. With two exceptions, Icelandic catches have been between 1,000 and 2,000 tonnes annually. The peaks seen in catches between 1980 and 1984, and between 1992 and 1994 were because spawning aggregations were found. Besides direct fisheries on the spawning grounds, the blue ling is mostly bycatch in redfish fisheries with bottom trawl. Most of the fisheries are in autumn and early winter along the continental shelf break to the south and west of the country.
Stock status (from the Marine Research institute)
In 2010, 6 900 t of blue ling (Molva dypterygia) were landed. In recent years, blue ling has mainly been taken as bycatch in the bottom trawl fishery. In 2008–2010, the proportion caught by longliners increased considerably as a result of targeting of blue ling by that fleet. Longlines now account for 60% of landings. Indices from the autumn survey indicate an increase in biomass and recruitment since 2005. However, survey results from autumn 2010 and spring 2011 indicate a decrease in stock size.
MRI considers the current high exploitation level unsustainable and recommends that landings be constrained to no more than 4 000 tonnes in the fishing year 2011/2012. The advice is to bring exploitation levels down to similar levels as observed in 2006– 2009. Furthermore, a continued closure of known spawning grounds from 15 February–30 April should be maintained.
References and further information
References: (Bergstad et al, 1998), (Magnúsdóttir et al, 1997) (Jónsson & Pálsson, 2006).
For full citation and further information on the main species in general see this page
Hreiðar Þór Valtýsson, University of Akureyri
