Survival of one-year-old artificially raised lobsters (Homarus gammarus) released in southern Norway

“Tiedemanns”, a private firm in Norway, initiated a lobster farming research programme in 1978, based on the production of larvae from wild ovigerous lobsters, and in 1982 a production plant at Kyrksæterøra with the capacity for 120000 one-year-old lobsters was completed. This site was chosen because of the availability of heated sea water from a smelter. Most of the young lobsters were released in western Norway where the natural stock is at a very low level, so that the effect of the release programme could easily be detected. It was later discovered that at least some of the hatchery-reared lobsters could readily be recognized in the commercial catch, since many of them had two pincer claws and were bluish in colour. In this article, we report the results of the yearly summer release of 7500 lobsters from 1985 to 1987 in a small area near Mandai. By 1990,50% of the catch from this area was identified as hatchery reared lobsters.