A sustainable no-kill sea urchin aquaculture method to obtain caviar

Sea urchin aquaculture represents a promising tool to promote blue economy principles that are geared towards the sustainable production of low-trophic-level organisms with high market and nutritional value. However, although sea urchin aquaculture has been practised for several decades, this sector has not yet achieved sustainable production and large-scale development outside China, mainly due to problems linked with long-term rearing cycles of most commercial sea urchin species. Here we present a method of sea urchin caviar production, called ‘raking’, that represents a technological advancement both in terms of the production approach and the final product. Raking is a no-kill method for the harvesting of caviar (sea urchin eggs) from female-only batches, meaning that the same sea urchins are used through several production cycles (three per year). Raking was compared with a traditional gonad enhancement method (known as ‘bulking’, where gonads are the final market product), and it proved to be more profitable through multi-cycle production, more sustainable without needing to kill the sea urchins to obtain the market product and able to overcome important biological and economic constraints of traditional sea urchin aquaculture.