Milkfish - WikiHQ

The milkfish (Chanos chanos) is a widespread species of ray-finned fish found throughout the Indo-Pacific. It is the sole living species in the family Chanidae, and the only living member of the genus Chanos.

The repeating scientific name (tautonym) is from Greek ( 'mouth'). They are grouped in the order Gonorhynchiformes and are most closely related to the Ostariophysi—freshwater fishes such as carps, catfish, and loaches.

The species has many common names. The Hawaiian name for the fish is awa, and in Tahitian it is ava. It is called bangús () in the Philippines, where it is popularly known as the national fish, although the National Commission for Culture and the Arts has stated that this is not the case as it has no basis in Philippine law. In the Nauruan language, it is referred to as . Milkfish is also called bandeng or bolu in Indonesia.

In 1877, the California Fish and Game Commission introduced one hundred milkfish from Hawaii to the inland waters of Solano County, California. The introduced population could not establish itself permanently and it is currently unknown how their presence affected the native ecosystem.

Milkfishes commonly live in tropical offshore marine waters around islands and along continental shelves, at depths of . They also frequently enter estuaries and rivers.

The following fossil species of Chanos are known:

Anatomy

The milkfish can grow to , but are most often no more than in length. They can reach a weight of about in pond. and an age of 15 years. They have an elongated and almost compressed body, with a generally symmetrical and streamlined appearance, one dorsal fin, falcate pectoral fins and a sizable forked caudal fin. The head is small relative to the body. The mouth is small and toothless. The body is olive green, with silvery flanks and dark bordered fins. They have 13–17 dorsal soft rays, 8–10 anal soft rays and 31 caudal fin rays. There are numerous fine intramuscular bones, which may complicate human consumption of the fish (see "Consumption" below).

Their silvery complexion is similar to many other fish species of the Indo-Pacific. They are often mistaken for species of Clupeidae, Megalops cyprinoides, Gonorhynchus gonorhynchus, and Elops machnata. Chanos can be distinguished from these species by their size, absence of scutes, tubercle on the lower jaw, fin placement, no gular plate between arms of the lower jaw, and having only four branchiostegal rays.

Variant milkfish body types have occasionally been found. The "goldfish-type" milkfish was discovered in the Philippines and is characterized by distinctly elongated dorsal, pelvic, and anal fins, and a caudal fin as long as the body. In Hawaii, Indonesia, and Australia, dwarf or hunchback 'shad-type' specimens have been recorded. They have a standard length-to-depth ratio of 2.0–2.5 instead of the usual 3.5–4.0. In Northern Australia, a milkfish with a red head, red fins, and blue dorsal coloration was reported.

Juvenile milkfish larger than typically bear the characteristics of adults. They have complete fin rays, a forked caudal fin, scales, and silvery coloration. Juveniles have been found to inhabit a diverse range of shallow-water ecosystems such as coral lagoons, estuaries, marsh flats, tidal creeks, and tide pools. Milkfish are good osmoregulators and extremely euryhaline.

The wide geographic distribution of milkfish has led to genetic variation in the species across the Indo-Pacific. Milkfish populations differ between the Hawaiian islands, the central Pacific islands, Tonga, Tahiti, Philippines-Taiwan-Indonesia, Thailand-Malaysia, India, and Africa. However, all populations are thought to be inter-breeding, thus they are all considered one species, and their genetic diversity is low. However, populations may still differ in their reproductive, migratory, and survival methods. Pollutants have also affected the aquaculture industry. In an aquaculture system in Butuan, Philippines, 97% of the fish sampled had microplastics in their gastrointestinal tracts. A similar study in Indonesia showed similar results. The presence of pollutants in milkfish poses a threat to the species' health, aquaculture, and humans.

Fishing

In the Philippines, it is illegal to catch adult milkfish (sabalo) measuring over . While the 1975 law was enacted in an effort to protect spawning stocks of fish, sabalo are still incidentally caught in fish corrals and are products of bycatch. This ban was reinforced by the Philippine Fisheries Code of 1998, which punishes violators with imprisonment for 6 months to 8 years, and/or a fine of , forfeiture of the catch and fishing equipment used, and revocation of their fishing license.

Popular presentations of milkfish in Indonesia include bandeng duri lunak (soft-boned milkfish, ikan bandeng is Indonesian for milkfish) from Central and East Java or bandeng presto, which is pressure cooked milkfish until the thorns are rendered tender, and bandeng asap or smoked milkfish. Either fresh or processed, milkfish is the popular seafood product of Indonesian fishing towns, such as Juwana near Semarang in Central Java, and Sidoarjo near Surabaya in East Java.

Milkfish is the most popular fish in Taiwanese cuisine; it is valued for its versatility as well as its tender meat and economical price. Popular presentations include as a topping for congee, pan fried, braised, and as fish balls. There is a milkfish museum in Anping District and city of Kaohsiung holds an annual milkfish festival.

Milkfish is an oily fish, and is rich in omega-3 fatty acids.

Aquaculture

History

thumb|left|Grilled bangus (milkfish) in the [[Philippine cuisine|Philippines]]

thumb|Global aquaculture production of Milkfish (Chanos chanos) in million tonnes from 1950 to 2022, as reported by the [[Food and Agriculture Organization|FAO]]

Milkfish aquaculture first occurred around 1800 years ago in the Philippines and spread to Indonesia, Taiwan, and into the Pacific. In 1980, the first spontaneous spawning happened in sea cages. These eggs were found to be sufficient to generate a constant supply for farms.

Milkfish aquaculture accounts for 14% of all aquaculture production worldwide. Indonesia and the Philippines were the leading producers of the species in 2017. The fish is especially desirable for aquaculture because of its rapid growth rate, disease resistance, acclimation to captivity, low mortality, high market value, and high-quality flesh.

Farming methods

thumb|left|Milkfish aquaculture in fish ponds in [[Cardona, Rizal, the Philippines]]

Fry are raised in either sea cages, large saline ponds (Philippines), or concrete tanks (Indonesia, Taiwan). Milkfish reach sexual maturity at , which takes five years in floating sea cages, but eight to 10 years in ponds and tanks. Once they reach , (eight years), 3–4 million eggs are produced each breeding cycle. Some still use the traditional wild stock method, capturing wild fry using nets. They can either be intensive or semi-intensive. Traditionally, this was made on site; food is now made commercially to order.

Processing and marketing

Traditional post-harvest processing include smoking, drying, and fermenting. Bottling, canning, and freezing are of recent origin.

Golden bangus

On April 21, 2012, a Filipino fisherman donated a milkfish with yellowish coloring to the Philippine Bureau of Fisheries and Aquatic Resources, which was later on called the "golden bangus". However, the fish soon died, allegedly because of a lower level of oxygen in the pond to which it was transferred.

Cultural significance

thumb|Street dancers in Dagupan depicting the bountiful harvest of bangus

Milkfish have appeared in the traditions and mythology of the native Pohnpeians, Hawaiians, Tongans, and Nauruans in the Pacific. Dagupan is considered the country's top producer of milkfish cultured in marine cages and pens. Two types of milkfish are cultured in the city, the more popular being Bonoan Bangus, often sold deboned and butterflied.

References

Francisco José Poyato-Ariza, A revision of the ostariophysan fish family Chanidae, with special reference to the Mesozoic forms (Verlag Dr. Friedrich Pfeil, 1996)

External links

Boneless Bangus
FishBase entry for milkfish
SEAFDEC milkfish hatchery info
DA, Philippines, About Bangus