42 Fish as feed inputs for aquaculture – Practices, sustainability and implications
degree of inter-annual variability that may depend upon extrinsic, often climate-
related factors. Furthermore, stocks may be highly migratory and, therefore,
often shared among more than one fishing nation. While it is possible to provide
science-based precautionary management of feed-fish stocks, political and
economic reality may combine to reduce management effectiveness, as typified
by the long period which it took to finalize the joint management of the northern
blue whiting stock. Furthermore, the ecosystem linkages between feed fisheries
and natural predators such as white fish, tunas, sea birds and marine mammals are
still not fully understood, and thus further precautionary thinking is necessary in
many cases.- Increased utilization of feedfish for human consumption: As mentioned earlier,
while feedfish from a number of feed fisheries are not suitable for direct human
consumption, other feedfish are. The main barriers to their direct use are not
so much technical but more related to market and other economic or cultural
influences. - Greater substitution by protein and oil substitutes: Substitutes for fishmeal protein
and marine fish oils are continuously being sought, and progress is being made.
Protein substitutes are already used in fish feed in the United Kingdom and
Norway, with up to 25 percent of the protein in the feed derived from plants. The
uptake of fish-oil substitutes has been slower. However, the level of substitution of
fish-based meals and oils possible is limited by their lack of essential amino acids
(such as lysine, methionine and histidine). Substitution at high levels may limit
growth. Another issue facing the plant meal and oil option in Europe is consumer
opinion and the affect that may have on the continued acceptance of farmed fish as
a “high quality” product similar to its wild counterpart. To produce a product as
“near to the wild product as possible”, research is also focusing on the “dilution”
of vegetable oils in the flesh when fish are fed diets containing 100 percent marine
fish oils for six months prior to harvest. In addition, vegetable oil substitutes
do not necessarily improve the environmental sustainability of the product (e.g.
increased soybean production may lead to further rainforest clearance).
7.2 The Americas
The region is home to three of the top four fishing nations in the world after China,
namely Peru (9.6 million tonnes in 2004), Chile (5.3 million tonnes) and the United
States of America (5.0 million tonnes). A very high proportion of the fish catch within
the region is destined for reduction and non-food uses (average of 47.2 percent), and
the region produced 57.3 percent of the total estimated global fishmeal and about 57.1
percent of the total global fish oil in 2005 (Tacon, 2009). According to the FAO, the
major pelagic reduction fisheries in the southeast Pacific Ocean have exhibited a general
decline in the three most abundant pelagic species: the Peruvian anchoveta, the South
American pilchard, and the Chilean jack mackerel. There is a lack of internationally
accepted criteria including fishery sustainability criteria, for monitoring ecosystem
impacts of reduction fisheries within the region.
Although total capture fisheries production within the region in 2004 was more than
12-times higher than aquaculture production, capture fisheries production has been
stagnant over the last decade (landings decreasing by 6 percent since 1995) compared
with aquaculture production within the region, which has been growing at an average
rate of 8.9 percent/year since 1995.
The domestic aquaculture sector within the region used 469 500 tonnes of fishmeal
(13.3 percent of total fishmeal production within the region) and 237 910 tonnes of
fish oil (35.1 percent of total fish oil production within the region) in 2004. The largest
consumers of fishmeal and fish oil within the region are salmonids and marine shrimp,
which accounted for 89.4 percent and 96.1 percent, respectivily, of the total fishmeal