Use of wild fish in aquaculture and its effects on income and food for the poor 399
fattening of bluefin tuna, that the practice is employed in a modern and expanding
industry. However, it is not clear to what extent the provision of feed, often pelagic
species, is obtained through specialized fisheries.
Apart from in Australia, fattening of bluefin tuna is now carried out in the eastern
Central Pacific (Mexico) and in several countries bordering the Mediterranean Sea.
Virtually all of the cultured bluefin tuna is shipped to Japan, where it enters the sashimi
market.
Overall, the amount of wild fish used annually as feed in this industry is probably
about 0.2 million tonnes. Most of this total is made up of small pelagic species
(Huntington and Hasan, 2009). Local fisheries generally provide this fish, while it is
reported that northwest African pelagic fisheries have been providing feeds to bluefin
tuna kept for fatting in the Mediterranean Sea. In most regions, the quantities so far
used are small in relation to pelagic fisheries in total^49.
Where supplies are removed from fish that normally would have been processed
into fishmeal, the effects on food supplies can generally be considered as small. The
effects on employment and income in the region where the fisheries take place could
be positive (value added in freezing, storing and transport of whole fish – probably
higher than the value added linked to fishmeal production), but overall the value is
likely to be small.
5.2.6 Conclusions
Feed fisheries, through aquaculture, generate employment and income for poor in
many coastal areas of the world. At the same time, they provide employment at sea
and in fishmeal factories for unskilled workers, particularly in South America and in a
few African countries.
Also, as a rule, these fisheries do not limit the access of the poor and undernourished
to fish as food. The exception to this rule may be fisheries that supply feed to capture-
based culture of tunas. Given the extraordinarily high prices paid for such tunas in
the Japanese markets, those who raise bluefin tuna in captivity can afford to pay more
for sardines and other pelagic species than do those who prepare this fish for the food
market (Zertuche-González et al., 2008).
Feed fisheries, in common with most marine fisheries, experience management
difficulties because fishers often exceed established catch limits. In many of these
fisheries difficulties are exacerbated by oscillations in the biomass of the species
concerned, oscillations that are linked to a fluctuating and changing marine environment.
Nevertheless, as these fluctuations follow varying rhythms, the fluctuations for the
sector as a whole will be less dramatic than that of any individual fishery, and overall
it seems plausible that the feed fisheries will continue to provide raw material to
fishmeal plants according to a pattern that will not differ much from the recent past.
The exception at present seems to be the North Atlantic feed fisheries. However, if
appropriate management action is taken in the North Atlantic fisheries, the world’s
feed fisheries are unlikely to be exploited by such high levels of fishing effort that these
fisheries will threaten overall yields of marine fisheries.
The above discussion of the use of fishmeal and fish oil in aquaculture feeds seems
to support the affirmation of Willmann (2005) that “Globally, evidence is weak, if any,
that expanding aquaculture has significantly contributed to increased fishing pressure
on reduction fish species. The primary reason for over-exploitation is the absence of
effective fisheries management and increase in the demand and price of food fish.”
(^49) However, the share can also be significant at the local level. It is reported that in 2006 about half of the
Pacific sardines (Sardinops sagax caerulea) landed in Ensenada on the west coast of Mexico was used as
feed in local capture-based culture of the northern bluefin tuna (Thunnus orientalis) (Zertuche-González
et al., 2008).