demersal habit. Their growth rate shows considerable regional variation and fish at one year old can measure , at 2 years old , up to at 13 years old. Their lifespan is around 14 years. The most important spawning grounds are in the waters off the central coast of Norway, off the southwest of Iceland, and over the Georges Bank. The fish which spawn in inshore waters are normally smaller and younger fish than those which occur in offshore areas. The younger fish have a spawning season which is less than half of that of the larger and older stock offshore. Once hatched the larvae do not appear to travel far from their spawning grounds, however some larvae spawning off the west coast of Scotland are transported into the North Sea through the Fair Isle-Shetland Gap or to the northeast of Shetland. In their larval stages, haddock mainly feed on the immature stages of copepods and the pelagic post-larvae up to in length prey on krill, Larvaceans, decapod larvae, copepods and on small fish. Once they have reached the settled, demersal, post-larval stage, benthic invertebrates become increasingly important although they still feed on pelagic organisms such as krill, however the benthic invertebrates form an increasing part of their diet as they grow. Adults prey on fish such as sand eels, Trisopterus esmarkii, American plaice, gobies, European sprat, and Atlantic herring, as well as capelin, silver hake, American eels and argentines. When a number of fish taken at the same time have their stomach contents sampled, the majority of stomachs contain similar prey, this suggests that haddocks feed in shoals. Shellfish, sea urchins, brittlestars and worms are also important prey, especially in the winter. Juvenile haddock are an important prey for larger demersal fish, including other gadoids, while seals prey on the larger fish. The recorded growth rates of haddock underwent significant change over the 30 to 40 years up to 2011. Growth has been more rapid in recent years, with haddock attaining adult size much earlier than was noted 30–40 years ago. However, the degree to which these larger, younger fish contribute to reproductive success of the population is unknown. The growth rates of haddock, however, have slowed in recent years. There is some evidence which indicates that these slower growth rates may be the result of an exceptionally large year class in 2003. The haddock stock periodically has higher