Capable of crawling across land using their pectoral fins, the climbing perch (Anabas testudineus) can survive out of water for several days. These indigenous tropical species thrive in lakes, rivers, and swamps, but they can also be found in brackish water habitats. Their accessory air-breathing organ, known as the labyrinth organ, allows them to thrive in oxygen-depleted waters.

This species can be found in Southeast Asian countries, including Malaysia, Thailand, Myanmar, and the Philippines. Climbing perch, locally known as liwalo and puyo, is a nutritionally valuable food fish that is also considered economically important. It provides essential amino acids, protein, fat, and other dietary requirements at a low price.

Declining wild populations 

In the Philippines, climbing perch is exclusively captured from the wild, creating pressure due to the growing demand. Recent findings indicated that the population of climbing perch in the wild is declining. According to the Philippine Statistics Authority (PSA), a decline was recorded in 2019, with only 1,805.27 metric tons caught, down from 2,072.38 metric tons in 2017. Moreover, climbing perch farming in the Philippines remains largely unexplored, making it a significant subject for research and conservation efforts.

Experts have recognized the potential for climbing perch aquaculture. Reports of successful captive breeding have emerged in other Asian countries, including India, Malaysia, Vietnam, and Thailand. Studies on hormone-induced breeding and seasonal reproduction strongly suggested that this species could become a viable aquaculture commodity. However, few initiatives exist to develop production techniques for climbing perch in the Philippines.

DA-FBC’s induced breeding technology

To address this problem, the DA-Fisheries Biotechnology Center (FBC), headed by Dr. Casiano Choresca Jr., Scientist I, explored the possibility of inducing breeding and producing climbing perch in captive conditions. Through this initiative, DA-FBC aimed to increase survival rates and revive climbing perch production to contribute to national food demand and security.

FBC is a biotechnology center housed within the NFRDI, promoting the use of biotechnology in fisheries research. The center also provides training and education to local stakeholders to foster the development and management of fisheries resources in the Philippines.

Induced breeding is a technique in which synthetic hormones are introduced to fish in captivity to stimulate breeding. While pituitary hormones are commonly used in this procedure, challenges with injection and preservation have led to the adoption of other synthetic hormones, such as LHRH-a and Ovaprim. This technique has already proven successful in breeding carps and catfish in other countries.

During the project, climbing perch were collected from the wild and conditioned for three months. Selected healthy samples were stocked in hapa net cages and fed commercial tilapia starter feed pellets. Female and male breeders were then chosen for the administration of sGnRHa hormone, a ready-to-use liquid formulation commercially available. A dose of 30 µg of hormone per gram of fish body weight was injected intramuscularly into the base of the pectoral fin using a sterile syringe. This method was performed quickly to avoid stressing the fish.

“The injected climbing perch were isolated in 20-liter plastic tubs, which were covered to create a dark environment conducive to spawning. In less than 24 hours, the climbing perch produced fertilized eggs, which were collected and transferred to hatching tanks enriched with a balanced mix of nutrients. The tanks were equipped with appropriate lighting, temperature, and aeration to support the eggs until hatching, which occurs 20-21 hours after fertilization,” explained Dr. Choresca.

The development of the climbing perch, from fertilized egg to juvenile stage, was closely monitored. Sampling was conducted to assess growth and survival rates, and grow-out experiments were also performed to optimize stocking density and feeding of climbing perch in ponds and cages.

Promising future for climbing perch

The project yielded positive results, demonstrating that induced breeding using sGnRHa is an effective technique for stimulating production in climbing perch. According to Dr. Choresca, high fertilization and hatching rates were observed, at 99 percent and 98 percent, respectively. Additionally, there was an 85 percent survival rate from larvae to fry and a 78 percent survival rate from fry to fingerling stage.

DA-FBC conducted a cost-return analysis that indicated favorable outcomes for this procedure. It presents a significant opportunity for climbing perch farming, with an increased survival rate and reduced rearing duration contributing to higher net income.

These findings demonstrate that induced breeding for climbing perch is feasible and offers a chance to enhance overall farm productivity. The paper titled “Improved Breeding and Seed Production of Climbing Perch in Controlled Tanks and Cage Systems” was published on May 23, 2024 in the Israeli Journal of Aquaculture, a peer-reviewed, open-access publication dedicated to scientific studies in aquaculture.

Moving forward, DA-FBC seeks to further develop techniques and methodologies for nursery rearing management to ensure high productivity and standardize protocols for the grow-out production of climbing perch.

As a fishing nation, the Philippines relies on fisheries research and development projects to secure sufficient resources for consumption and provide livelihoods for its people. Innovative projects and advanced techniques are essential for ensuring the sustainable production of economically important commodities, such as climbing perch. Thanks to this initiative, there is now a hopeful outlook for the production and conservation of climbing perch. ### (Vanessa Mae Escaño)