The General Fisheries Commission for the Mediterranean (GFCM) of the UN Food and Agriculture Organization (FAO) have embarked on a campaign to replenish stocks of sea urchins in the waters of the Bay of Naples in Italy.
The area of focus encompasses the waters off the small volcanic island of Procida, a region known for boasting a rich and dynamic marine ecosystem. The GFCM aquaculture team recently completed a field visit on sea urchin aquaculture to collect materials and conduct underwater research in order to launch a pilot action on sea urchin restocking.
The purple sea urchin (Paracentrotus lividus) is considered to be one of the most important herbivores in the Mediterranean Sea and is a famous culinary delicacy in many countries. As one of the organisms defining the ecological system in the region, P. lividus has long been used as an animal model in developmental biology and as an indicator in the assessment of environmental quality.
Contrary to what their robust appearance may suggest, sea urchins are very sensitive to environmental conditions, especially in the early stages of life, and they require intensive monitoring and special attention during the production process. The overall status of the sea urchin populations in the Mediterranean is therefore of concern.
As a precaution pending formal stock assessments, sea urchins should be considered in need of conservation due to the impacts of fisheries and climate change, among other factors. Nevertheless, their numbers, spread, and impacts are different around the region depending on local conditions and harvesting.
Given the importance of the species as a resource for fisheries and the determinant role it plays as a macroherbivore, regulating the volume of algae and helping to maintain balance in the ecosystem, the GFCM's pilot action aims to support effective and innovative restorative aquaculture practices as a solution to revive sea urchin populations.
Within this pilot project, the GFCM is working to support and advise aquaculture enterprises that are involved in the production and restocking of sea urchins in the Mediterranean and Black Sea region. One such enterprise is Echinoidea, a small-scale aquaculture facility in Procida, that was established in 2016 by Michele Trapanese, who manages the farm with his two children Chiara and Filippo. Echinoidea is combining business with conservation to achieve advances in the production of farmed sea urchins, which are valued for their delicious roe, and in the restocking of sea urchin populations in the area.
The farm produces urchins in a closed recirculating aquaculture system (RAS) and was successful in leading preliminary experiments of artificial fertilisation and rearing of sea urchins in collaboration with the research institute Stazione Zoologica Anton Dohrn.
Following the collection of mature urchins in the Gulf of Naples, female and male gametes are extracted from individuals selected for in vitro fertilisation in the laboratory, and the juveniles obtained are placed under continuous surveillance and controlled rearing conditions (temperature, water quality and feeding) over the course of the entire production cycle, which usually lasts about nine months. Once the adults are ready, they are released back into their natural environment to continue growing in an area specifically intended for aquaculture.
The GFCM said that although the Procida pilot project still requires further development and coordination with stakeholders, it has the potential to become a model case study for echinoculture that could be expanded across the Mediterranean Sea.