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Dieren en planten

Fish   Herring family   Herring   Sprat   Fish biology   Fish communities   Marine fauna   Sea fish   
  • Dut: Haring (bankharing, bliek, doggerharing, kanaalharing, zuiderzeeharing, noordharing, Noorse haring, Noordzee haring, IJslandse haring, Baltische haring, Buchanharing, Downsharing, Røgenharing)
  • Lat: Clupea harengus
  • Eng: Herring
  • Ger: Hering
  • Fren: Hareng
  • Dan: Sild
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Herring, Ecomare

Herring

Herring are found in coastal seas down to a depth of two hundred meters. They form large schools during the day just above the sea bottom or in deep water. In the evening, this school swims in the direction of the water surface where it disperses for the night. Herring can age to twenty years old and reach a length of 40 centimeters. In reality, there are even rarely any seven or eight-year old herring swimming around any more. Herring feed on zooplankton and fish larvae, which they sift out of the water with the help of filters located on the inside of their gills. They are heavily preyed upon by birds, other fish and people. In 2002, the herring stock finally emerged from the alarming situation in which this species found itself in the 1990s.

  • Populations

    There are more populations of herring that spawn at different moments and have other differences in fertility. In the North Sea, there are three major populations, which live together outside of the spawning season. During spawning season, each population gathers together in its own spawning grounds. The Buchan-Shetland herring spawn in August and September off the coast of Scotland and the Shetland islands. The Doggersbank herring spawn in the central part of the North Sea between August and October. The Southern Bight of Downs herring spawn in the English Channel from November till January. The further south the spawning grounds, the later the spawning. A fourth herring population spawns in the spring in the Baltic Sea and migrates via the Skagerrak to the North Sea. This is the population which provides the first young herring so desired in the Netherlands, and are caught up till the end of May in the Skagerrak. The various species of herring often differ very slightly due to the difference in temperature and salinity of the water in which they hatch.

  • Zuiderzee herring

    There used to be a fifth population of herring: the Zuiderzee herring. This population used the former Zuiderzee (presently the IJsselmeer) as spawning grounds and nursery. In the past, these herring swam into the Zuiderzee during the spring and summer to spawn. Fishermen, dolphins, seals and porpoises made use of this trek to fill their bellies. The Zuiderzee herring disappeared when the Afsluitdijk was finished and the IJsselmeer was created. Or so it was believed. In 2006, the TX10 caught a Zuiderzee herring. The fishermen recognized the population by its shorter and thicker build. The Zuiderzee herring also has fewer vertebrae. After the Zuiderzee was closed, the populations probably mixed with other herring populations so that they did not become totally extinct.

  • Reproduction in the North Sea

    In the spawning grounds, the females in the entire school release the roe simultaneously and the eggs are fertilized by the males at the same time. Spawning takes place just above the sea floor. The slimy eggs sink and attach themselves to the bottom. Depending upon the water temperature, they hatch after 8 to 40 days. The larvae drift to their nursery, which is located primarily along the eastern shores of of the North Sea and west of Schleswig-Holstein and Denmark. Young herring remain in the nursery for 2 years, in shallow nutrient-rich water. After two years, they swim to deeper waters. Herring become sexually mature between 3 and 5 years old and spawn every year till they die.

  • Herring as consumption fish

    Seen worldwide, herring belongs to the top 5 most important species for the fisheries. Every year, around 1.5 million tons of herring are caught around the world. Only anchovies, coal fish, Chilean hake and silver carp are caught more.
    The herring season for the Dutch fleet begins at the end of May and continues till the following March. This fleet fishes herring mostly in the western North Sea and around the Scottish islands. Most of the herring caught is further processed into pickled or canned products.
    Only one fifth to one third of the total herring yield can be processed into salted herring. This is herring that has not developed any soft or hard roe. The fat percentage begins around 15% and increases in the period between May and July. The rate of fatty increase depends upon the amount of animal plankton available for the herring.

  • Distribution of the herring
    Spawning grounds and nurseries of the herring, Ecomare
  • The herring stock in the North Sea
    Spawning and catch of the herring (North Sea), Ecomare

    The spawning stock of herring in the North Seas was more than 2 million tons in 2003. This was followed by a decline. In 2007, the spawning stock was estimated at no more than 1 million tons. New year classes since 2003 continue to be weak. The cause is unknown. Fishery biologists counted very few herring larvae by the spawning grounds in early 2008, which seems to indicate that the declining trend has not yet ended.
    Since the spawning level is quickly declining, the quota have been lowered. In 2008, the TAC for the entire North Sea is 130,000 tons and the quotum for the Dutch fishermen is 40,000 tons.

  • Herring farts

    In the 1980s and 1990s, the Swedish hunted mysterious submarines. The Swedish-Russian relationship remained very tense because the Swedish regularly sensed underwater submarines that they could not find. When the East Block fell apart and the noise continued, studies proved that the noise was farts made by herring. The fish release gas from their swimming bladders and the sound is intensified at greater depths.