Small Scale Laboratory Culture of the Ormer, Haliotis Tuberculata

Abstract

A simple aquarium system was used to keep large ormers collected from the wild and to rear juveniles from fertilization up to age one year. Spawning was induced by exposure to u.v. irradiated sea water and counts made of gamete production. Repeated spawning was observed in males and from egg counts it was inferred that females also undergo repeat spawning in the wild.Juvenile ormers were reared on simple collectors up to 4 mm shell length and later in open mesh cages. There was large variation in growth rate between individuals among the juvenile ormers. After one year shell lengths varied in the range 6·2–21·o mm.Twenty-three adult ormers (shell length 40·4–93·6 mm) were reared for eight months in a tank with a concrete shelter. The smaller ormers remained under the shelter much more than the larger ones, some of which adopted a permanent position outside the shelter. In the study period growth was greater in the smaller specimens (less than 70 mm shell length) than in the larger ones.