According to the Food and Agriculture Organization of the United Nations (FAO) Milkfish (Chanos chanos) is one of the most important food fish species in the world. In Indonesia, Taiwan and the Philippines, more than a quarter of a million tonnes of milkfish are harvested annually in brackish ponds, which represents about 60% of the total fish production from aquaculture in Southeast Asia. This huge amount sourced from a single fish commodity is projected to further increase in the coming years to meet the dietary protein needs of the ever-growing population in Southeast Asia.
Milkfish farming in Southeast Asia started about six centuries ago. Culture methods in a variety of enclosures are constantly being improved upon. The traditional milkfish industry depended totally on an annual restocking of farm ponds with juvenile fish reared from wild-caught fry. Seasonal and annual variations in fry availability made the industry vulnerable. During the past decade, research focused on the mass production of fry in hatcheries to become independent from wild-caught fry. However, it seems this hasn't been taken up completely. Large quantities of fry are still taken from the Ocean and that causes another problem:
Milkfish fry fishery, an important industry in the Philippines, uses non-selective fishing gears and push nets in coastal areas which lead to the capture of other non-targeted juvenile aquatic species. Unfortunately, information on the amount and the identity of by-catch species is lacking thus the extent of impact of the fry fishery is not known.
A new study from the Philippines shows that by-catch fish species of the milkfish fry industry included various marketable food fish, culture species and aquarium trade species. The researchers used DNA Barcoding to identify postlarval and juvenile fish samples that were collected from the catch of local fishers using traditional fishing gears and push nets, with milkfish fry as target species.
By-catch in fisheries is a well known global problem. In 2003 it was estimated that approximately 20 million metric tonnes, representing about a quarter of the total world catch are actually by-catch. This represents a serious threat to biodiversity and coastal ecosystem integrity. The present study shows the utility of DNA Barcoding in identifying the juvenile fish species threatened as by-catch in fry fishery. It proves to be very valuable in aiding management efforts for the sustainability of these natural resources.