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. Sea urchin gonads are high-demand culinary delicacies, and depleted wild populations of these echinoderms have spurred efforts to culture them sustainably. This study presents a sea urchin aquaculture method that produces ‘caviar’ made of eggs produced by female batches, without needing to kill the sea urchins.