Purple sea urchin barrens are causing mass deforestation of kelp in California and Oregon, impacting ecosystem function, fisheries and coastal communities alike. This presents an opportunity to bring together environmental organizations, fishers and aquaculture practitioners to address the issue. Using aquaculture, commercially valueless wild purple urchins can be ranched to enhance their roe production, potentially leading to restoration of kelp forests and a revival of sea urchin fisheries, all while supporting commercial aquaculture activity. Sea urchin ranching is gaining worldwide popularity with greater prevalence of urchin barrens, but an understanding of the feasibility in terms of the economics are required for the nascent industry to advance.
This project seeks to develop an economic model based on an accounting of operating costs of prototype ranching systems for purple sea urchins. Commercially acquired urchins were ranched for 10 weeks in three prototype systems: land-based flow-through tanks, land-based recirculating tanks, and sea-based cages. Basic aquaculture metrics beyond the standard observations of farm staff were measured and recorded by the project team, including gonad index and color. An economic model will be developed by assessing the likely costs of production at commercial scale of each ranching system. A set of microsimulation models will be constructed for each of the prototypes based on collected data from the 10-week trial, which will then be used to investigate a wide range of scenarios about the effects of costs, scale, and markets on the economic and financial feasibility of urchin ranching operations.
Results will advance business management of a sustainable marine aquaculture industry on the West Coast by providing critical information necessary for prospective urchin ranchers to develop business plans. It is anticipated that this project will highlight potential net benefits of commercial aquaculture which will increase communications and trust between environmental groups and fishery associations potentially reducing negative perceptions of aquaculture generally.