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

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

Peru), while the highest contaminant levels in the same groups (as above) originate

from Europe (SCAN, 2000; Joas, Potrykuse and Chambers, 2001; Easton, Luszniak

and Von der Geest, 2002; EC, 2002; Hites et al., 2004a, 2004b; Foran et al., 2005).

Moreover, as a general rule since the majority of these contaminants are fat soluble and

tend to bio-accumulate within

fatty animal tissues, contaminant

levels tend to be highest within

longer-lived and more fatty

pelagic fish species (anon., 2003;

Korsager, 2004; Oterhals, 2004).

As a consequence of the

natural accumulation of POPs

within fish fatty tissues and fish

oil (SCAN, 2000; Bell et al., 2005)

and the fact that aquaculture is

already using over 82.2 percent of

total global fish oil supplies (see

Section 3.3), it is believed that

dietary fish oil inclusion levels

within aquafeeds will decrease

in the long run as global supplies

remain limited (Figure 24) and

fish oil prices continue to rise

(Figure 46), and by so doing ensure the continued growth of the fish oil-dependent

marine/brackishwater aquaculture sector (Tacon, Hasan and Subasinghe, 2006).

A similar situation is expected with fishmeal, where rising prices (Figure 43)

(Pescaaldia, 2007) and decreasing supplies (for various reasons, including the possible

increased use of traditional forage fish species for direct human consumption) will force

the aquaculture industry (for purely economic reasons) toward the increased use of

more sustainable non-food grade feed resources as dietary fishmeal replacers, including

the increased use of terrestrial agricultural animal and plant by-product meals.

FIGURE 46

Comparative prices of fish oil used in salmon feeds in Chile, Peru

and Argentina

Source: anon (2007)

FIGURE 47

Major differences between conventional extensive, semi-intensive and intensive farming

systems in terms of production, resource use and potential/perceived environmental risks

Source: Adapted from Tacon, Phillips and Barg (1995)