Barrens of gold: an economic opportunity that benefits the environment.
The native purple urchin, Heliocidaris erythrogramma, is overabundant on many rocky reefs in southeastern Australia, leading to overgrazing of productive kelp beds. Commercial harvest of this edible sea urchin could aid kelp recovery. However, the lack of kelp in these areas results in urchins with small, poor quality roe that is undesirable. However, improving urchin roe quantity and quality through sea urchin farming could lead to an exciting new aquaculture industry that would have both ecological and economic benefits.
Urchins from barrens can reach commercial quality
Sea urchins collected from urchin barrens and fed our custom high-quality diets can produce commercial quantities of roe during and outside of the harvest period. During the 2016 harvest period, urchins from barrens fed a high-protein diet increased roe yield by up to 2.8 times compared to wild urchins.
Results of our 2017 experiments using urchins collected from barrens in Port Phillip Bay show that specialised feeds (numbers 1 to 18) increase roe weight up to 18% of urchin weight (out-of-season; March-June) and 22% (in-season; June to September). This is a vast improvement in roe weight compared to wild urchins sampled on the barrens at the beginning (WS) and end (WF) of each experiment. Wild urchins from barrens always had low and non-commercial roe weights of just 3 to 5%.
For details of our AgriFutures grant, visit: http://www.agrifutures.com.au/related-projects/solving-key-industry-bottlenecks-for-sea-urchin-roe-enhancement/