The saithe is a large codfish, usually between 70 and 110 cm long in catches, but the largest individual caught in Icelandic waters measured 132 cm.
The saithe can be described as benthopelagic fish, i.e., it occurs both close to the bottom and in the water column. It has a streamlined shape and is consequently a very good swimmer. It can swim rapidly all over large distances. Fishes tagged in other European waters have been recovered in Icelandic waters. The saithe is native to European waters from Murmansk in the north to the English Channel in the south. It is also found around the Faroe Islands, in Greenlandic waters and from Labrador to Cape Cod in North America.
The saithe feeds primarily on pelagic organisms. Krill is the most important food for young fish but is also consumed by large individuals. Capelin and sandeels are the most important foods for larger saithe, but other fishes are also eaten to a lesser extent. Growth is rather rapid, and the saithe reaches sexual maturity at the age of 5 or 6 years.
The saithe is found all around Iceland but is rarer in the colder waters to the north and east of the country. Spawning takes place along the south and southwest coasts, from January to March; earlier than other codfishes. In mid-June, the juveniles are very common in shallow waters all around Iceland. They gradually move into deeper waters as they grow older.
Catches have been from 30 000 to 130 000 tonnes annually since 1950. Almost all the current catches are by Icelandic boats, but the saithe was also an important catch for the German fleet, when it conducted its fisheries in Icelandic waters.
The current catches are mostly taken with bottom trawl and spread rather evenly over the year. However, considerable amount also used to be taken by gillnetters. The saithe both sustains direct catches and exists as a bycatch in cod and haddock fisheries. Most of the catches are along the continental shelf break, off the south and west coast. Presumably, these are the main feeding grounds for the saithe. Fisheries for juvenile saithe with fishing rod are also popular with human juveniles in harbours all around Iceland.