A comparison of three land-based containment systems for use in culturing green sea urchins, Strongylocentrotus droebachiensis (Muller) (Echinodermata: Echinoidea)

Abstract

Worldwide, most sea-urchin populations are in decline. Future market demands will likely be met through aquaculture, which may consist of gonad enhancement of wild-caught sea urchins. In this context, we examined three land-based containment systems for suitability in maintaining commercial-size green sea urchins (Strongylocentrotus droebachiensis). Mortality rate, gonad quantity, gonad quality (colour, brightness, firmness, texture) and cleaning efficiency associated with each containment system were the criteria for comparing the effectiveness of the systems (large raceways, small raceways and washtub tanks). After 6 weeks, urchins maintained in large raceways displayed significantly higher mortality rates than urchins maintained in either the small raceways or washtub tanks (mean±SD: 24.3±10.4%, 8.0±3.5% and 4.3±1.5% respectively). Significant differences in cleaning time were detected among the three systems with washtub tanks requiring significantly more cleaning time (0.11±0.02 min urchin−1) than the other two systems and large raceways requiring significantly less cleaning time (0.06±0.02 min urchin−1) than the other two systems. No significant differences in gonad characteristics were detected among the three containment systems. Because of the higher mortality rate in the large raceways and the increased cleaning time required for the washtub tanks, the small raceways were considered to be the best of the three systems tested.