The overabundance of sea urchins on southern Australian reefs has caused widespread ecosystem change, transforming lush kelp forest into underwater desserts called urchin-barrens. Massive removal is necessary, but culling is not cost-efficient. Creating a capture-based roe-enhancement urchin industry is a pathway for economic sustainable urchin removal, but if it is successful, reefs will be restored and urchins will no longer be abundant, with the industry making itself extinct.
Closed life-cycle culture of urchins is a way to reduce the risk of a marooned industry. The purple urchin, Heliocidaris erythrogramma, has characteristics that make it a prime target for aquaculture, as it produces non-feeding, fast-developing larvae. Yet, no standardized aquaculture protocols exist for this species of sea urchin.
To improve production rates across multiple life-stages, we tested the effects of different broodstock diets on larval and post larval survival, discovering a strong link between egg quality and settler performance. We investigated optimal temperatures and stocking densities for larvae, as well as efficient grow-out diets, and optimal grow-out temperatures.
Here, we summarise our research and discuss the outlook of this novel aquaculture industry.