Use of wild fish and other aquatic organisms as feed in aquaculture in the Asia-Pacific 81
FIGURE 10
Types of trash fish/low-value fish of single species caught and used in Asian aquaculture- USE OF FISHMEAL AND FISH OIL IN ASIAN AQUACULTURE
The preference for the use of fishmeal and fish oil in all forms of diets for cultured
stocks is based on their favourable amino acid and fatty acid profiles, respectively, which
provide all of these essential nutrients. These products are easily digested by aquatic
animals and also provide unknown growth factors, some essential micronutrients and
highly unsaturated fatty acids, all of which cannot be synthesized de novo in adequate
quantities by most cultured stocks, particularly marine finfish.
Fishmeal and fish oil are manufactured from trash fish/low-value fish put through
a “reduction process”. The raw material used in industrial reduction processes is
also referred to as “forage fish”. Globally, the main species used on a large scale
to manufacture fishmeal and fish oil are small pelagic species such as anchovetta
(Engraulis ringens), sand eels (Ammodytes spp.), Atlantic menhaden (Brevoortia
tyrannus), capelin (Family Osmeridae, e.g. Mallotus spp.), Atlantic herring (Clupea
harengus harengus), Chilean jack mackerel (Trachurus murphyi) and chub mackerel
(Scomber japonicus). On average, 4–5 kg of wet fish will yield 1 kg of fishmeal and
100 g of fish oil (FAO, 1986; De Silva and Anderson, 1995). However, in Asia, as will
be discussed later, fishmeal manufacture is based on a species mix, and seafood industry
waste is also being increasingly used. In addition, there is a trend to utilize processing
waste from cultured fish such as pangasiid catfish in Viet Nam and rohu in Myanmar
to extract fish oil and also as a protein source in feeds.
4 .1 Historical aspects of the use of fishmeal and fish oil in aquaculture
Prior to the third quarter of the last century, aquaculture was not seen as a major fish-
food production sector, the harvest from the oceans was thought to be inexhaustible,
and fishmeal and fish oil use in aquaculture was negligible. Most of the global
production of these commodities was used by the terrestrial animal husbandry sector.
However, with the growth of the aquaculture sector, particularly salmonid culture in
the Northern Hemisphere, the demand for fishmeal and fish oil began to increase. The
first warning signs were given by Wijkstrom and New (1989) and New (1991, 1997),
who suggested that the growth of the aquaculture industry could be limited by the
availability of fishmeal.
Over the last 30 years, aquaculture production has grown from 8.52 million tonnes
valued at US$12 billion in 1984 to 54.37 million tonnes valued at US$57 billion in 2004,
an average annual rate of increase of 6.8 percent (FAO, 2007). As this growth was