By Rafael D. Guerrero III
We were in Indonesia for an international aquaculture conference. Indonesia is one of the top fisheries producers of the world. In 2015, the country ranked fourth in world aquaculture production. Of the country’s 17.6 million metric tons of fisheries production, 74% was from aquaculture.
There are 2.5 million hectares of freshwater areas available for aquaculture in Indonesia. Freshwater aquaculture production in the country was 3,043,161 metric tons in 2015. The main freshwater fishes cultured are catfishes (Clarias spp. and Pangasius),
Nile tilapia, common carp and giant gourami.
The production of the anabantid (Family Anabantidae) and herbivorous (plant-eating) giant gourami (Osphronemus gouramy), a native of Indonesia, was 113,407 metric tons
in 2015. Grown in freshwater ponds and cages on the islands of Java and Sumatra, the fish is highly-valued for its “thick, tasty flesh with no fine bones.” It is also commercially farmed in China, India, Sri Lanka, and other Southeast Asian countries.
In western Java, farmers breed the giant gourami in earthen ponds that are 200-700 m2 in area and 0.7-1.5 meter deep. The female has a rounded dorsal fin, reddish color, and fleshy lips while the male has a pointed dorsal fin, darker color, and high forehead. The breeders are stocked at a sex ratio of one male to two females at a density of 100-150 m2
per fish. The male builds the nest with the bamboo branches and aquatic plants (e.g., Typha) provided. While the fish usually spawns in the wild during the dry season, it can spawn at any time in ponds.
According to studies by T. Amorasakun and co-researchers of the Prince of Songkla University in Thailand, the female giant gourami becomes sexually mature at a weight of 968 grams and age of about a year. It has a relatively low fecundity (number of eggs produced) of 5,500 eggs/fish. The round and floating fertilized eggs hatch in about 26 hours (28-30OC) with a hatching rate of 62%. The yolk-sac of the fry is completely absorbed about 50 hours from hatching and feeding on zooplankton like Moina begins.
The fry are reared to fingerling size of three centimeters in length in rearing ponds for three months with feeding of Azolla pinnata and supplemental feeds like rice bran and peanut waste. For stocking in grow-out ponds, the fingerlings are further grown to sizes of 5-8 centimeters for another two months. The fish are fed with the leaves of papaya, taro and other plants until they attain marketable sizes of 0.7 to 1 kilo each after 8 months to 1.5 years of culture. It can also be polycultured with other fishes like the nilem (Osteochilus hasselti), tawes (Barbus gonionotus) and common carp (Cyprinus carpio).
Like other anabantids, the giant gourami has an accessory breathing organ known as the labyrinth which is located behind each of the gill chamber that enables it to breathe atmospheric air. It can grow up to a size of 0.7 meter long and is known to have a lifespan of 20 years.
This appeared in Agriculture Monthly’s January 2020 issue.