The herring’s (Lat. Clupea harengus linnaeus) habitat is in the North Atlantic, from the Barent Sea to the Byscaya Bay, and from Greenland, Labrador south to Cape Hatteras in North Carolina in the USA. Herring is found all around Iceland. It is an up to mid sea species, which spawns on the ocean floor. It can be found between 20 and 250 metres depths. It does not seem to be much affected by the salinity of the sea, and is sometimes found wandering into river estuaries.
It feeds mainly off crustaceans and krill. Many fish species feed off its roes, especially the haddock. Both the mature herring and its fries are eaten by many fast swimming species, i.e. Pleurotremata and cod. Birds, seals and whales, especially killer whales, prey on it as well.
Three stocks of herring have been discovered around Iceland, two Icelandic (spring and summer spawning stocks) and the Norwegian spring spawning stock, which migrates into the Icelandic fishing zones for feeding during summer. The Icelandic summer spawning stock breeds in the bays and fjords off the northwest, north, and northeast coasts until it is two years old. During the third year it migrates to the ocean south of the country, where it spawns as well as off the west coast.
The Norwegian stock, which migrated earlier to Icelandic waters, spawns off the west coast of Norway. Mature herring came here to feed, when spring started in the ocean. In June or in the beginning of July, it had arrived at the fishing grounds off the north coast. Late in the sixties the stock collapsed, most likely because of the overexploitation of the young herring.
During the second autumn of the herring’s life, it reaches 7-10 centimetres length and 10 grammes in weight. The next summer its length is double and its weight reaches 50-70 grammes in its third year. The summer spawning stock reaches puberty at the age of four and its estimated maximum age is 20-25 years.
Photo Credit: Gervais et Boulart