A pump-pot nursery system for rearing juvenile New Zealand dredge oysters Tiostrea lutaria

A wave-operated nursery system was developed for growing hatchery-produced spat of the New Zealand dredge oyster Tiostrea lutaria (Hutton) through to a size (approximate to 20 mm) suitable for on-growing in conventional oyste r farming equipment. The pump-pot enabled cultch-free dredge oyster spat to be transferred from hatchery upwellers at a small size (>2mm), thus avoidi ng the need to supply them with cultured algae to maintain a high growth ra te. The wave-activated pumping action of the pot maintained a sufficient fl ow of water through the pot to achieve rapid growth of small spat held at h igh densities.