Distributes in western part of the Sea of Japan and the East China and Yellow Sea northward to Muroran, Hokkaido, Japan.

HABITS:

Found in inlet waters, occasionally entering brackish waters. These fish are carnivorous, fresh or frozen fish, such as horsemackerel, mackerel, anchovy, sand eel, and saury are used for food. Minced flesh is recommended for fish less than 100 mm in length, but larger fish can be fed chopped flesh. The farming of puffer is generally carried out in the warmer areas since the puffer requires water temperatures between 10° and 29°C.

SPAWNING:

Fish moves offshore with growth, and breeds from March to May. When spawning fish attaches eggs to rocks in the areas at depths of around 20 m. Liver and ovaries are extremely toxic but flesh, skin and testes not poisonous. Methods for artificial propagation of puffer were developed in Japan in 1960 and are now used commercially. Expansion of puffer farming will require greater production of seedlings through artificial propagation.

GROWTH:

Seedling fish of about 3 g are transferred from the hatchery to the growing net cages in July and should average 550 g by August of the following year. At the end of one and half year, the puffers can reach 800 g (the minimum market size), and after one additional year will weigh 1.5-2.0 kg.

USES:

Puffers, known as globefish or blowfish of the genus Fugu, are in high demand as a luxury food in Japan even though certain species are extremely toxic. Fugu rubripes rubripes, is used principally for farming ventures. The toxicity of puffers changes seasonally, and becomes the greatest in the spawning season from May through June. The toxic substance "Tetradotoxin" occurs mostly in the ovary, liver, intestines and skin, and rarely in the muscle. When prepared carefully by licensed cooks in Japan, puffers are completely safe to eat. The buffers are commercially cultured species with extremely high value in Japan. These fish are also cultured and used for high-value seafood and Chinese medicine.

CULTURE:

Puffer farming depends on the capture of partially grown fish in the spring, rearing these fish to market size in net enclosures, and marketing them in the winter when demand and price are high. Larger fish, 40-60 cm in length, weighing 1.5 to 2.5 kg, can be fed in enclosures from spring to early winter and then shipped to market. Younger fish, about 200 g when captured, require another year before reaching market size. The procedures for rearing puffers are similar to those used in the culture of yellowtail. The fish are fed 4 times a day during midsummer, 3 times a day from September to November, and less frequently during the winter and early spring. Puffers stop feeding in winter when the water temperature falls below 14°C, and this causes a weight loss of about 10% during the winter. Production of puffers in fish farms has decreased during recent years because of a shortage of seedlings.

REFERENCES:

Masuda, H., K. Amaoka, C. Araga, T.Uyeho, and T. Yoshino. 1984. The fishes of the Japanese Archipelago. Vol 1 (text). Tokai University Press, Tokyo, Japan. 437 Page (text), 370pls.

www.lib.noaa.gov/japan/aquaculture/report 1/glude2/html: Marine fish culture in Japan