Study

A mark-recapture study of hatchery-reared juvenile European lobsters, Homarus gammarus, released at the rocky island of Helgoland (German Bight, North Sea) from 2000 to 2009

  • Published source details Schmalenbach I., Mehrtens F., Janke M. & Buchholz F. (2011) A mark-recapture study of hatchery-reared juvenile European lobsters, Homarus gammarus, released at the rocky island of Helgoland (German Bight, North Sea) from 2000 to 2009. Fisheries Research, 108, 22-30.

Actions

This study is summarised as evidence for the following.

Action Category

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

Action Link
Subtidal Benthic Invertebrate Conservation
  1. Transplant/release captive-bred or hatchery-reared species - Transplant/release crustaceans

    A study in 2000–2009 in one area of rocky seabed off Helgoland, German Bight, North Sea (Schmalenbach et al. 2011) found that after releasing one-year-old hatchery-reared European lobsters Homarus gammarus, they grew and survived in the wild, became reproductive, and appeared healthy. Recaptured lobsters had grown in the wild (females: 14.5–19.8; males: 16.8–21.8 mm/year) and reached 85 mm (legal catch size) within four to seven years after release. Survival rate of lobsters released in 2000 and 2001 was estimated at 32 and 39% respectively after up to five years. In addition, no recaptured lobsters displayed signs of “Black Spot” disease, 95% had developed a crusher-claw, and 16% of recaptured females carried eggs. Annually in 2000–2005, at two locations of 10 m water depth, tagged hatchery-reared lobsters were released at the surface (5,421 lobsters in total). Released lobsters weighed 1.5 g and had carapaces 15 mm long. Between 2000 and 2009, 488 of these were recaptured at least once, using lobster pots, traps, and divers. It is not known if the number of uncaught tagged lobsters was due to mortality, recapture effort, or migration outside the search zone. Recaptured lobsters were sexed, observed for signs of disease and presence of a crusher-claw, and their carapaces measured. Percentage survival was estimated from the mark-recapture programme data obtained between 2001 and 2005 for the 1,036 released in 2000 and 2001.

    (Summarised by: Anaëlle Lemasson)

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