The transformation of macro-algal dominated rocky reefs into urchin barrens due to grazing pressure from overabundant sea urchins is a global phenomenon. Removing urchins from barrens by culling (smashing with hammers) can help re-establish algal cover, yet this practice is too costly for broad-scale application. Removal through harvesting urchins for their roe (gonad) by commercial fishers is also not financially feasible, as urchins in barrens are often malnourished, which results in unsalable, poor-quality roe. Creating an economic driver to remove urchins from barrens by making each urchin valuable through roe enhancement aquaculture, could be a better, more cost-effective solution.
Roe enhancement involves capturing urchins from the wild and feeding them with an urchin specific diet in an aquaculture setting to increase the quantity and quality of their roe. High quality urchin roe is a prized delicacy in the Asia-pacific region and here we demonstrate that the overabundant purple sea urchin (Heliocidaris erythrogramma) collected from barrens in Port Phillip Bay, Victoria, can be effectively roe enhanced in 12 weeks to create a marketable product. Furthermore, we show feed composition and culturing conditions can influence the quality and quantity of roe produced. If scaled up appropriately, the development of a roe enhancement aquaculture industry could be a cost-neutral management option for controlling overabundant purple sea urchin populations in Victoria.