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

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

(Huntington et al., 2004; Worm et

al., 2006; Skewgar et al., 2007).

5.2 Trash fish and baitfish

Direct environmental impacts

include:

• increased environmental
  pollution resulting from the
  use of highly perishable and
  water-polluting trash fish-based
  feed items (Tacon et al., 1991;
  Ottolenghi et al., 2004);


• increased biosecurity and disease risks of feeding unpasteurized trash-fish
  products back to cultured fish and/or wild fish through bait use (Gill, 2000;
  SCAHAW, 2003; Hardy, 2004; anon., 2005);


• increased fishing pressure on wild juvenile target species for fattening and on
  pelagics for feeding/bait use (Dalton, 2004; Ida, 2006); and


• increased use of trash fish may also include the captured juveniles of higher-value
  commercial food-fish species and consequent risk of overfishing on available fish
  stocks (FAO, 2004).

Indirect social impacts include:

• increasing trash fish prices due to high demand for trash fish for use as aquaculture
  feed, which may place these fish out of the economic reach of the poor and needy
  for direct human consumption as an affordable food source (Edwards, Tuan and
  Allan, 2004).

5.3 Krill

Despite the fact that there are over 85 known species of krill (Nicol and Endo, 1997)

and that total reported krill landings reached over 1 118 165 tonnes in 2004, only one

krill species is currently reported, viz. Antarctic krill (Euphausia superba) (FAO,

2006a). In view of the important ecological role played by krill in marine food webs, it

is imperative that all krill species be reported and quantified by fishers for transparency,

traceability and the long-term sustainability of the krill fisheries sector (Nicol, 2006;

Murphy et al., 2007). Removal of large quantities of krill from the marine ecosystem

may have adverse long-term ecosystem impacts on dependent species, and in particular

for many protected marine mammals and birds (Reid and Croxall, 2001; Hill et al.,

2006).

marine ecosystem and potential

ecosystem and biodiversity impacts

upon other dependent piscivorous

animal species, including other

fish species, birds and mammals

6. POTENTIAL ALTERNATIVE USES OF FEED-FISH SPECIES
   6.1 Increased use of traditional feed-fish species for direct human
   consumption
   6.1.1 Frozen and preserved products
   As mentioned previously, an increasing portion of the catch of Chilean jack mackerel
   and other pelagics (e.g. Patagonian grenadier and chub mackerel) is being processed
   for direct human consumption (Figure 48). Despite the fact that the average price for
   frozen jack mackerel and fishmeal is very similar (Figure 49), the reported fishmeal and
   fish oil yield from jack mackerel is about 23 and 5–7 percent, respectively, in contrast

FIGURE 49

Chilean prices for major product lines

Source: SUBPESCA (2005)