Iceland scallop

Scientific: Chlamys islandica. English: Iceland scallop. Icelandic: Hörpudiskur. For more languages see the Marine Animal Dictionary.

Biology and distribution

Iceland scallop occurs all around Iceland but is most common in the fjords off the west and northwest coast. The normal habitat is a hard sea bottom at depths of 15-80 m. They are most abundant in fairly strong nutrient rich currents where they filter-feed on phytoplankton and small zooplankton. Scallops grow rather slowly and mainly in the spring and early summer months. The Iceland scallop reaches maturity at 4 to 5 cm shell height at the age of 5 to 7 years. Ten year old scallops measure 6.5-8.5 cm in height and the largest individuals measured about 16 cm in height. Spawning takes place in June/July. Scallops are unique among bivalves since they are able to swim in a limited way.

Many scallop species are found all around the world, and many of them are of commercial importance. The Iceland scallop is the only scallop species that is commercially exploited in Iceland. It is a sub-arctic species that occurs from the Gulf of St. Lawrence up to the southern part of Baffin Island, off the southern part of Greenland, Iceland, Jan Mayen, northern Norway, Spitsbergen, Franz-Josef Land, off the entire coast of Siberia and in the Pacific from Northern Japan, up to Alaska and then down to British Columbia.

Catch and fishing methods

The Iceland scallop has been harvested in Icelandic waters since 1969, mostly in Breiðafjörður Bay in West Iceland. It used to be the most important mollusc fishery in Iceland and since 1980 the annual catch has been in the range of 10,000 tonnes annually, highest 17,068 tonnes in 1985. However, no scallop fisheries have been conducted since 2004 due to a stock collapse due to a parasite infection.

The Iceland scallop was caught by dredging along the sea bed at a depth of 20-70 m. The season traditionally extended from late July and throughout winter with the best fishing in the autumn months.

Poisons may accumulate in shellfish following algal blooms in the height of summer. Although a fairly rare occurrence in Iceland, this phenomenon must be kept in mind by those who like to collect fresh shellfish for eating whole from the shell. The poison is most frequently found in the gonads. Scallop processing in Iceland involves separating and quick-freezing the adductor muscle only, which does not accumulate the poison.

Stock status (from the Marine Research institute)

The Iceland scallop (Chlamys islandica) fishery remained closed during the 2010/2011 fishing season.

Survey indices declined drastically between 2001 and 2008, with the 2010 index amounting to only 14% of the average from 1993–2000. The downward trend in stock abundance is due to increased natural mortality, probably caused by protozoan infestation in adult scallop. Recruitment has been poor in the period 2004–2009. MRI therefore recommends a continued closure of the scallop fishery for the quota year 2011/2012.

Processing and markets

Only the abductor muscle is eaten from the scallop; it is, however, a very large part of the soft tissue. The scallop is considered a delicacy and is especially good when fried with butter and served with a good white wine.

References and further information

References: (Gunnarsson et al., 1998), (Garcia et al., 2006), (Garcia, 2006a).

For full citation and further information on the main species in general see this page

Hreiðar Þór Valtýsson, University of Akureyri