Atlantic halibut

Scientific: Hippoglossus hippoglossus. English: Halibut, common halibut, Atlantic halibut. Icelandic: Lúða, flyðra, heilagfiski. For more languages see the Marine Animal Dictionary.

Biology and distribution

The Atlantic halibut is among the largest of bony fishes in the world with a maximum recorded size of 4,7 m. It is found over most of the North Atlantic and a close relative, the Pacific halibut (Hippoglossus stenolepis) is to be found in the North Pacific. It occurs all around Iceland but is more common in the warmer waters to the south and west of the country. It spawns in very deep waters at around 2,000 m depth. Around the age of one year, the juveniles appear in shallow waters, where they stay for about two years. They gradually move deeper, and at the age of 9 to 10 they join the adults, which spend most of their time in deep waters. The Atlantic halibut matures around the age of 7 to 14, the males earlier than females.

As are most flatfishes, the Atlantic halibut is a benthic fish usually found on a sandy or muddy bottom. It migrates widely over a considerable depth range as mentioned before. It is a voracious feeder, eating whatever it can handle, mostly other fishes.

Catch and fishing methods

The Atlantic halibut has probably been caught in Icelandic waters since people settled in that country, but not in any high numbers before the start of this century. Catches by Icelanders have been rather stable in the past going from 200 to 500 tonnes before the Second World War and 500 to 1,500 tons annually thereafter. These official figures, however, have to be viewed with caution as a relatively large part of Atlantic halibut catches in Iceland are for local consumption, and are possibly not reported in catch statistics.

The first British trawler came to fish Icelandic waters in 1891, and their numbers increased rapidly until the trawler fishery was fully developed at the turn of the century. It is often assumed that they were primarily after the cod. That is not the case, as the most sought after catch was flatfishes, mainly plaice and Atlantic halibut. American schooners from Gloucester had also been targeting Atlantic halibut between 1880 and 1890, this being the only record of substantial fishing activity by Americans in Icelandic waters. Official catch figures are only available after 1905, but at that time catches were already around 8,000 tonnes, more than 10 times higher than catches in recent years. A drop in British catches after 1907 suggests that overfishing may already have reduced Atlantic halibut stocks at that time.

Direct targeting of the Atlantic halibut is only by longline. This fishing method has virtually been abandoned in recent years due to low catches. However, because of its voracious feeding habits and large-scale movements, the Atlantic halibut is a bycatch in most other groundfish gears. Danish seines operate in shallow waters and catch mostly young halibut. Trawlers operate deeper and the Atlantic halibut caught by this gear are mostly between 3 and 7 years. The fishery that targets Atlantic halibut, however, operates in deeper waters than most other fishing gear. Presumably they are almost exclusively fishing older and larger Atlantic halibuts, but no samples are available from this fishery.

The Atlantic halibut stock around Iceland is now considered to be at a very low level, facing many problems. This is a very large and valuable stock. It is a bycatch in most types of fishing gear over a wide area so managing the Atlancti halibut catches is difficult without seriously affecting other the fishing of other species. Furthermore it starts to appear in fishing gear at the age of two, about 10 years away from maturity. Taking all this into account, we have a species that is seriously overfished.

Aquaculture

Atlantic halibut ranching has recently become successful in Iceland, see more on that subject on the pages dealing with aquaculture.

Stock status (from the Marine Research institute)

In 2010, 580 t of halibut (Hippoglossus hippoglossus) were landed. From 1996 onwards, annual landings have been less than 1 000 t, the lowest observed since 1905. Halibut has mainly been taken as bycatch in the bottom trawl and longline fisheries. In recent years, the biomass indices from the groundfish survey has declined sharply. Currently, the halibut stock seems to be severely depleted, with very little recruitment into the spawning stock in recent years. The Ministry of Fisheries has issued a regulation where a ban is set on directed fishery for halibut. This is an important step in protecting the stock.

Processing and markets

The Atlantic halibut is one of the most popular fishes for consumption in Iceland. It has been a very welcome bycatch in cod fisheries throughout the centuries. As the current Atlantic halibut catches are very low it is not surprising that a considerable part of the current catch goes to local consumption. About half of the reported catch is exported fresh, either by air or sea but the rest is frozen. As with so many other flatfishes, the main market is the United Kingdom but a large part is also exported to Asia, mainly Japan but also China.

Atlantic halibut is best eaten fresh and can be cooked in a variety of ways, boiled, baked, fried or barbecued. It is a quality food and its firm and dense texture is sought after by restaurants all over the world.

References and further information

References: (Björnsson, 1995), (Kristinsson, 2003), (Jónsson & Pálsson, 2006).

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

Hreiðar Þór Valtýsson, University of Akureyri