Fishes

About 340 fish species have been recorded within the Icelandic EEZ. About half of these are demersal, i.e. they are usually associated with the bottom; the other half are species that live in the water column. Fish production is dominated by relatively long-lived species, such as herring, codfishes, redfishes and flatfishes. The capelin is the most obvious exception here; it is pelagic, its life span is short and it dies after spawning. Many species are migratory, but most of the important species do not generally leave the Icelandic EEZ. The main exceptions are capelin, Greenland halibut, blue whiting, oceanic redfish and Atlanto-Scandian herring. Occasionally some quantities of mackerel, horse mackerel, squid and blue-fin tuna migrate to Icelandic waters.

Fishes in Icelandic waters can broadly be split up into 3 groups according to feeding habits; zooplankton feeders, benthic feeders and piscivorous (fish eating) fishes. The most abundant species are the zooplankton feeding species, dominated by 2 pelagic species in Icelandic waters, capelin in the colder waters and herring in the warmer; they mostly eat copepods. Other abundant pelagic or benthopelagic species in the waters around Iceland, such as redfishes, blue whiting, and sandeels feed predominantly on euphausids but also on other zooplankton and benthic invertebrates to some extent. These fishes are themselves important food for many other fish species.

The main benthic feeding fish species, or groups, are haddock, catfishes, skates and flatfishes. Most of these also eat other fishes, mostly capelin when available. Higher in the trophic level are the piscivorous fishes, dominated by cod in warmer waters and Greenland halibut in colder seas. Other species at this trophic level are mostly gadoids, such as saithe, whiting, tusk, and lings, but other less numerous groups are Atlantic halibut, monkfish, sharks and dogfishes. In general, species in this group eat mostly small invertebrates when small, and then gradually shift to other fish when fully grown.

A number of smaller or much rarer species are also found around Iceland, living in the shadow of these larger and more abundant ones. Many species of sculpins (cottidae) live hidden among kelp or rocks; these are predators on even smaller animals. A number of eelpout (zoarcidae) species are probably the most common fish species in the deep, cold waters north of Iceland. These eat a variety of benthic invertebrates and are in turn eaten by cod and Greenland halibut. Similar-looking butterfishes (Pholis gunnelus) are the most common fishes along the seashore and longer and more slender snake-blennies (stichaeidae) live at intermediate depths all around the country. Sticklebacks (Gasterosteus aculeatus) are also found along the seashore, as well as in freshwater. Many species of snailfishes (lipridae) occur around Iceland, most are jelly-like and live in the deep, cold northern waters. Many small codfish species are abundant, especially Norway pout (Trisopterus esmarkii) in the warmer waters, and polar cod (Boreogadus saida) in the colder waters.

The midwater realm is also home to many and extremely diverse looking species. Many of them, such as scabbard fishes (trichiuridae), anglerfishes (order lophiiformes) and dragonfishes (stomiidae) are ferocious looking, entirely black with huge mouths and large, sharp teeths. These mostly feed on other fish species, including each other. Smaller groups, such as lanternfishes (order Myctophiformes), hatchetfishes (Sternoptychidae), searsidae (platytroctidae) and anglemouths (gonostomatidae) have more conventional looks and mostly feed on zooplankton. Many eel species (order anguiliformes) also live in this environment. Many of the midwater (mesopelagic) species can be abundant, and there has been some interest in fishing these, but it has not proved to be economically feasible. Although numerous groups have been mentioned here, this is just a brief overview of the most abundant species or groups, many others are present and still others occasionally visit Icelandic waters.

About 30 fish species are regularly harvested in Icelandic waters. Pelagic fisheries in Icelandic waters have mostly targeted capelin and herring. Recently blue whiting catches have increased dramatically and, even more recently, mackerel catches have also increased. Demersal fisheries usually target a mixture of codfish, flatfish and redfish species. Other species of some, but lesser, importance are catfishes, monkfish and lumpsucker. A few species of sharks and skates are also fished but are of low economic importance. All these economically significant species are described further under the heading “Main species”.

References and further information

References: (Vilhjálmsson 1997), (Björnsson & Pálsson 2004), (Jónsson & Pálsson 2006).

For full citation and further information on marine life in general see this page

Hreiðar Þór Valtýsson, University of Akureyri