Growth, reproductive cycle, and movement of berried European lobsters (Homarus gammarus) in a local stock off southwestern Norway

Published source details Agnalt A., Kristiansen T.S. & Jørstad K.E. (2007) Growth, reproductive cycle, and movement of berried European lobsters (Homarus gammarus) in a local stock off southwestern Norway. ICES Journal of Marine Science, 64, 288-297.
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This study is summarised as evidence for the following.

	Action	Category
	Transplant/release captive-bred or hatchery-reared species - Transplant/release crustaceans Action Link

Transplant/release captive-bred or hatchery-reared species - Transplant/release crustaceans

A controlled study in 1998–2000 in one area off southwestern Norway, North Sea (Agnalt et al. 2007 - same experimental set up as Agnalt et al. 2008) found that hatchery-reared female European lobsters Homarus gammarus released into the wild had similar growth rate and movement patterns, compared to wild females. Regardless of carapace length, the growth rate of hatchery-reared females (7–10 mm between moults) was similar to that of wild females (3–8 mm). In total, 53% of hatchery-reared females remained within 500 m of their release sites, which was similar to wild females (41%). Between 1990 and 1994, hatchery-reared juvenile lobsters (approximately 128,000) were released as part of a restocking program. During the fishing season each year from 1998 to 2000, egg-bearing female lobsters caught by fishers were measured (total length, carapace length), weighed, and hatchery-reared females were differentiated from wild females by the presence of tags. All females were then retagged, kept in holding pens in the sea, and released after the end of the fishing season to potentially be recaptured by fishers the following fishing season (mark-recapture). A total of 81 hatchery-reared females and 231 wild females were recaptured at least once. Locations of release and recapture sites were recorded.

(Summarised by: Anaëlle Lemasson & Laura Pettit)