Restorative Aquaculture: How Commercially Important Sea Urchins Can Aid in Coral Reef Recovery

Stacey Williams

 Institute for Socio-Ecological Research, Puerto Rico

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ABSTRACT

Sea urchins are commercially important as their gonads, also known as roe or uni, are considered a delicacy in many countries. However, sea urchins also play an important ecological role as they are the main herbivores in marine habitats. Herbivores are essential on coral reefs as they control the abundance of benthic algae, which would otherwise outcompete corals and other benthic organisms for space. Currently, many Caribbean coral reefs lack herbivores and are dominated by macroalgae and a dangerous encrusting alga, Ramicrusta spp. The Institute for Socio-Ecological Research (ISER) has developed a novel approach in improving coral reefs by enhancing sea urchin populations in Puerto Rico through restorative aquaculture techniques. ISER is executing two different techniques to produce urchins for restoration purposes. Post larval settlers of the long spined sea urchin, Diadema antillarum, are collected from the field, brought back to the laboratory, and grown to a young adult size. Recently, we developed a small scale hatchery and have been closing the life cycle of the West Indian sea urchin, Tripneustes ventricosus, in the laboratory. More than 5,500 lab-reared D. antillarum and more than 300 T. ventricosus, have been restocked to coral reefs all around Puerto Rico. Significant changes in the benthic structure were observed during the first week after the restocking. Significant reductions of fleshy macroalgae (Dictyota spp.) and thick turf algal/sediment mats (TAS), both unsuitable substrates (e.g., coral settlement), contributed to this change. Additionally, preliminary observations show that coral outplants have a higher chance of surviving when herbivores are present because they do not need to compete for space against cyanobacteria and macroalgae. Our work shows that producing sea urchins through aquaculture techniques provides direct ecological benefits to coral reefs and should be integrated in all coral restoration plans.

HOW TO CITE: Williams S.M, 2026.  Restorative Aquaculture: How Commercially Important Sea Urchins Can Aid in Coral Reef Recovery. Contribution 5.3, p346 IN CRFM, 2026. Volume I: Technical Papers. Presented at the CRFM 20th Anniversary Scientific Conference, 28-31 August 2023. CRFM Special Publication No. 37, CRFM Secretariat https://www.crfm.int/index.php?option=com_k2&view=item&id=927

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4 June 2025, Dominica--The Regional Seminar for the Project for Strengthening Sustainable Use and Management of Coastal Fisheries Resources in the CARICOM Countries (COASTFISH) has just concluded in Dominica after two days of spirited engagements.

Hon. Jullan Defoe, Minister of Agriculture, Fisheries, Blue and Green, Economy, Dominica, welcomed the attendees during the opening ceremony held yesterday.

The purpose of the regional seminar was to disseminate the outputs, achievements, good practices and lesson learned across several project activities which focused on strategies and actions to achieve co-management as a tool for resource management and for fostering better livelihoods. The ultimate goal is to further expand the co-management approach established during the project to the wider Caribbean, in line with the overall project goal.

The COASTFISH Regional Seminar brought together fishers and fisheries officials from the project's six participating countries: Antigua and Barbuda, Dominica, Grenada, Saint Kitts and Nevis, Saint Lucia, and Saint Vincent and the Grenadines. Two experts from the Caribbean Regional Fisheries Mechanism (CRFM) Secretariat, Dr. Sandra Grant - Deputy Executive Director and Dr. Maren Headley - Programme Manager, Fisheries Management and Development, provided integral technical support and delivered presentations during the course of the two-day event. Dr. Joeli Veitayaki, University of South Pacific, delivered a lecture on "The role of co-management in Fisheries Association in South Pacific Country," while Dr. Mitsutaku Makino, University of Tokyo, delivered a lecture on "Tool Box in Blue Economy in the Fisheries."

The Japan International Cooperation Agency (JICA)-funded COASTFISH Project, implemented through IC Net Ltd. of Japan in collaboration with the CRFM has successfully supported a diverse range of pilot initiatives across the region aimed at enhancing the sustainability and resilience of coastal fisheries.

Here are some highlights:

• Among the pilot activities were the construction, deployment, and monitoring of artificial reefs designed to boost the recruitment of juvenile species such as the spiny lobster in nearshore marine environments. An important link to the tourism sector was also showcased through the use of artificial reefs as a dive attraction, and highlighted intersectoral linkages within the blue economy.

• Countries also piloted the construction of fish pots with biodegradable panels to reduce ghost fishing, the use of zinc anodes to combat fish trap corrosion, and the application of pop-up tags to deter theft of fish pots.

• The project further supported activities in sea moss farming and processing, including the development of value-added sea moss products.

• Fish preservation techniques, such as fish salting and product marketing were also promoted. In addition, a lionfish derby and culinary initiatives featuring lionfish recipes aimed to raise awareness and promote the consumption of this invasive species were undertaken.

• To support data-driven management of marine resources, a juvenile queen conch abundance survey was conducted to assess current population levels and inform fishery management strategies.

• Capacity-building was a key component of the project, with training provided in fish processing, product development, facility management and also dive certification for fishers.

• Coral gardening activities were also implemented, contributing to habitat restoration amid growing threats such as coral bleaching and disease.

• In keeping with its commitment to inclusivity, the COASTFISH Project piloted gender mainstreaming initiatives to increase the participation and leadership of women in the fisheries sector.

The success of these pilot initiatives highlights the value of regional collaboration and innovation in strengthening coastal communities and ensuring the long-term sustainability of marine resources in the Caribbean, using a co-management approach and highlighting the roles of fishers.

Closing remarks were made by Mr. Hisashi Suzuki, Deputy Director General of JICA, Dominican Republic who noted the successful outcomes of the project. Mr. Andrew Magloire, the project consultant, praised the excellent collaboration of all the partners.

On behalf of its Member States, the CRFM Secretariat thanks the Government and people of Japan for the support provided to the region through the Japan International Cooperation Agency (JICA).