New oyster on-growing container for German mariculture operations

Abstract

The hydrographic and climatic situation along the German coast requires specially adapted equipment for mariculture enterprises. The containers used in the past for the on-growing of oysters ( Crassostrea gigas Thunberg) in shallow sea areas provided results which gave reason for developing a new type of container which was to be more economic and produce a high quality oyster of uniform shape. Small prototype containers, based on a galvanized iron construction, were built and placed at different sites along the coast. They held 1680 oysters, each of which were re-attached with cement onto square mesh plastic netting which was stapled on oak frames. On these frames, which were handled like drawers, the oysters had optimal conditions which were believed to be better than on a natural oyster bed. Each oyster had its own space of 7 cm by 8 cm wide and 10 cm high and was not handled until it reached market size. Good water exchange was provided by the open construction of the container which also gave protection against predators by means of a complete mesh cover.