Fish as feed inputs for aquaculture: practices, sustainability and implications

78 Fish as feed inputs for aquaculture – Practices, sustainability and implications

The use of farm-made feeds based on trash fish/low-value fish and/or other animal

protein sources (mainly processing waste from poultry) is still a common practice in

freshwater and marine carnivorous finfish culture and crab and lobster fattening in

Asia. However, in some instances there are trends to change from the use of farm-

made feeds to commercial feeds, the most notable of these being in catfish farming in

the Mekong Delta, a sector that has witnessed an explosive growth in the last decade

and was estimated to have had a production volume of over 1 million tonnes in 2007

(Phoung and Oanh, 2009). The snakehead and catfish farming sector in Thailand is

predominantly based on farm-made feeds (see Boxes 2 and 3), but these feeds are

predominantly based on the use of poultry processing wastes and in such feeds the

amount of ingredients originating from aquatic organisms is often negligible, with

exceptions such as in pangasiid culture in Viet Nam (see Section 5.2).

In contrast to “farm made” feeds, commercially manufactured feeds are produced in

large quantities in central manufacturing plants and are purported to be in accordance

with the dietary requirements of individual species. Rarely, more generalized feeds

that are reckoned to be useable and effective for a whole range of cultured finfish are

also available in the market. In Asian aquaculture, some of the commonly found feed

types are those for tilapias, shrimp, eels, seabass and catfishes. Often such feeds differ

marginally in their specifications for different stages of the grow-out cycle of each

of the species, and of course, between species. It is not uncommon that in intensive

culture systems, the feed costs often account for more than 50 percent of the recurring

costs of an operation.

In general, there is very limited quality control of commercial feeds in the region,

perhaps with the exception of countries such as Thailand (personal observation). This

as an area where investigation is needed, especially in view of the proliferation of small-

scale feed mills in the region and the ever-increasing product certification requirements

BOX 3

Snakehead culture

Snakeheads are difficult to wean on to pellet feed, and hence the industry continues

to depend upon moist feeds that include about 70–80 percent trash fish. However, a

number of small hatcheries are now beginning to wean the wild-caught snakehead fry

on to pellet feed, initially feeding a mixture of pellet feed and minced trash fish and

gradually reducing the latter. The fish can be completely weaned on to a dry diet in 10

to 12 days. An increasing number of grow-out farms are beginning to obtain weaned

fingerlings, and in a few years, it can be expected that snakehead farming in Thailand

will be transformed almost completely, as was seabass farming.

Photos: Feed bag covers and the hatchery set up used for weaning snakehead