EXPERT TOPIC MILK FISH
MILK FISH
EXPERT TOPIC A Philippine tradition By Matthew Holmes, Features editor, International Aquafeed
T
he milkfish is an important seafood in Southeast Asia and some Pacific Islands. Because milkfish is notorious for being much bonier than other culinary fish, deboned milkfish, also called boneless bangús in the Philippines, has become increasingly more popular in stores and markets. Milkfish aquaculture first occurred around 800 years ago in the Philippines and spread in Indonesia, Taiwan, and into the Pacific. Traditional milkfish aquaculture relied upon restocking ponds by collecting wild fry. This led to a wide range of variability in quality and quantity between seasons and regions. In the late 1970s, farmers first successfully spawned breeding fish. However, these were difficult to obtain and produced unreliable egg viability. In 1980, the first spontaneous spawning happened in sea cages, whose eggs were then found to be sufficient to generate a constant supply for farms. Fry are raised in either sea cages, large saline ponds or concrete tanks. Milkfish reach sexual maturity at 1.5kg (3.3lb), which takes five years in floating sea cages, but eight to ten years in ponds and tanks. Once they reach 6kg (13lb), 3–4 million eggs are produced each breeding cycle. This is mainly done using natural environmental cues. However, attempts have been made using gonadotropin-releasing hormone analogue (GnRH-A) to induce spawning. Some still use the traditional wild stock method, which is capturing wild fry using nets. Milkfish hatcheries, like most hatcheries, contain a variety of cultures, for example, rotifers, green algae, and brine shrimp, as well as the target species.
34 | October 2018 - International Aquafeed