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

Use of wild fish and other aquatic organisms as feed in aquaculture in the Asia-Pacific 79

of importing nations. With an exception of a study carried out in Bangladesh (Kader,
Hossain and Hasan, 2005), such investigations on feed quality are rather uncommon
and have to be intensified and, where appropriate, more stringent regulations
introduced with respect to types of feed ingredients and their quality. A schematic
representation of the efficacy of the broad feed types on the growth of cultured stocks
is shown in Figure 8.

3.3 Ingredients used
The ingredients utilized in fishfeed production vary widely depending on the feed
type, the cultured stock(s) and the farmers’ financial limitations. Basically, they range
from agricultural and animal industry by-products to fishmeal and fish oil, among
others. A detailed account of the availability of commonly used ingredients and the
type of usage in Asian aquaculture, particularly of agricultural by-products, has been
presented elsewhere (Tacon, 1987; Hertrampf and Pascual, 2000; De Silva and Hasan,
2007; Hasan et al., 2007).

3. 4 Use of fish and other aquatic products in aquaculture
   Fish used directly and/or reduced into a form such as fishmeal or fish oil to feed
   cultured stocks are referred to as trash fish/low-value fish. Recently it has been pointed
   out that the use of the term “trash fish” is misleading and that a better term would be
   “low-value fish”, which has been defined as “fish that are generally of relatively low
   economic value and typically small sized; they can be used for human consumption or
   as animal feeds (both fish and livestock); they may be used directly in both aquaculture
   to feed other fish or processed into fishmeal/oil for incorporation into formulated diets;
   the same is true for human food, where the fish may be consumed directly, or further
   processed often using traditional methods of processing small fish” (Sugiyama, Staples
   and Funge-Smith, 2004). Trash fish/low-value fish have also been defined as: “Fish that
   have a low commercial value by virtue of their low quality, small size or low consumer

FIGURE 8

A conceptual representation of the effectiveness of fertilizers and different feed

types on production

Source: De Silva and Hasan (2007)