Mangrove crab farming has long been an important source of livelihood for many coastal communities in the Philippines. According to the Philippine Statistics Authority (PSA, 2020), total mangrove crab production reached 20,766.25 metric tons, with an average price of Php 395.94 per kilogram. However, the continued loss of mangrove habitats and declining wild stocks have posed significant challenges to the industry’s sustainability.

Recognizing the need for science-based interventions, the Department of Agriculture–National Fisheries Research and Development Institute (DA-NFRDI) initiated studies to develop and refine methods for culturing mangrove crabs under controlled conditions.

Research and findings

Through the Marine Fisheries Research and Development Center (MFRDC) based in Guiuan, Eastern Samar, NFRDI researchers have been improving hatchery and nursery techniques to enhance juvenile survival rates and reduce fishing pressure on wild populations.

In collaboration with the NFRDI-Brackishwater Research and Development Center (BFRDC) in Lanao del Norte and the Bureau of Fisheries and Aquatic Resources (BFAR) Regional Field Offices, NFRDI conducted verification trials and field studies across several regions, including Cagayan Valley, Bicol region, Eastern Visayas, and Northern Mindanao. These studies tested various nursery setups, feed types, stocking densities, and environmental conditions.

Results indicated wide variations in growth rates, ranging from 0.01 grams per day during the early nursery phase to 3.68 grams per day in later stages. Survival rates were highest in Eastern Visayas, where water conditions were more stable compared to typhoon-prone areas. Researchers also observed that commercial shrimp feeds performed comparably to natural feeds, offering a more accessible and cost-effective option for fish farmers.

Mapping mangrove crab resources

Beyond hatchery and nursery trials, NFRDI also conducted a nationwide assessment of mangrove crab resources between 2020 and 2021. Published in 2022, the Resource Assessment of Mangrove Crabs in the Philippines identified three major Scylla species, S. serrata, S. tranquebarica, and S. olivacea, across 34 buying stations located in Cagayan Valley, Bicol Region, Eastern Visayas, and Northern Mindanao.

Findings showed that S. serrata, the preferred species for aquaculture, was most abundant in Cagayan Valley, Bicol, and Eastern Visayas, while S. tranquebarica dominated in Northern Mindanao. This data serves as a valuable reference for local governments and communities, guiding decisions on conservation, aquaculture zoning, and resource management.

Recognition of research excellence

In October 2024, the NFRDI-MFRDC team received the Gold Award for Best R&D Paper at the National Research Symposium organized by the Department of Agriculture–Bureau of Agricultural Research (DA-BAR). The award-winning study, Technology Verification on the Nursery Production of the Mangrove Crab, Scylla serrata, in the Philippines, was presented by Senior Researcher Cristan Campo and was selected from 142 entries for its robust scientific methodology and practical applications.

The study recommended optimal stocking densities to prevent overcrowding, maintenance of water quality to minimize losses during extreme weather events, and the use of nursery sheds to protect young crabs from temperature fluctuations. It concluded that nursery farming remains a profitable stage in mangrove crab aquaculture, providing stable income opportunities for small-scale farmers.

Capacity building and technology transfer

To further disseminate research outputs, NFRDI developed a Training Module on the Nursery Culture of Mangrove Crabs in Pond Net Cages under the AquaBiz School and Technology Business Incubation (ABS-TBI) Program. The module compiles years of fieldwork and verification trials into a comprehensive, step-by-step guide on nursery establishment and management.

Designed for both researchers and practitioners, the module covers essential topics such as site selection, pond design, feeding regimes, water management, and techniques to reduce cannibalism among crabs, one of the major challenges in nursery culture. It also integrates lessons from partner institutions such as the Food and Agriculture Organization (FAO), the Southeast Asian Fisheries Development Center (SEAFDEC-AQD), and BFAR.

Looking ahead

Mangrove crab aquaculture exemplifies the intersection of traditional livelihoods and modern research. NFRDI’s sustained efforts, from assessing wild stocks to developing hatchery and nursery technologies, demonstrate how science can drive sustainable growth in the fisheries sector.

Through continued collaboration, research, and capacity-building initiatives, NFRDI aims to ensure that mangrove crab farming remains a viable and resilient industry for future generations, preserving both livelihood and legacy in the country’s coastal communities. ### (Ann Dominique Del Valle)