Use of wild fish and other aquatic organisms as feed in aquaculture in the Asia-Pacific 115
killed other species but also destroyed the coral environment were often employed to
catch these fish (Pet, 1997; Sim, 2005). With the development of grouper mariculture
through the closing of the life cycle of many cultured groupers (whose culture is, of
course, dependent on trash fish/low-value fish as a feed source), the restaurant trade
has switched almost completely to cultured live fish. This change has undoubtedly
helped preserve coral habitats and also reduced impacts on biodiversity.
8.2 Impacts on human health
Reports indicating that human health has been impacted because people have eaten
cultured fish which were fed unhealthy fish do not seem to exist. However, the public,
animal and environmental health impacts of aquaculture have become a relatively
controversial issue that has attracted much public attention in recent years from a
series of viewpoints (Garrett, dos Santos and Jahncke, 1997; Feare, 2006). It has been
speculated that adverse impacts resulting from aquaculture can negatively influence
human health and indeed could nullify the relatively well defined health benefits that
are known to be derived from fish consumption (e.g. de Deckere et al., 1998; Horrocks
and Yeo, 1999), at least from a public perspective. The accumulation by farmed stocks
of organic and inorganic contaminants from feed and/or the environment is one
such issue (Hites et al., 2004). The dioxins (which include polychlorinated dibenzo-
p-dioxins and dibenzofurans) have attracted the most attention (Lundebye et al.,
2004). However, by using properly formulated feeds, the dioxin-like polychlorinated
biphenyls (PCBs) can be significantly reduced in farmed fish (Berntssen, Lundebye and
Torstensen, 2005).
Legislation on the level of dioxins permitted in farmed fish was introduced by the
European Union (EU), while public health concerns such as mad-cow disease (bovine
spongiform encephalopathy (BSE) have led to a ban on the use of animal industry
by-products in animal feeds. The legislative and regulatory aspects of feeds have been
reviewed by Tacon, Hasan and Subasinghe (2006), and it is sufficient to state that
Asian aquaculture currently lacks such regulations. Indeed, to make matters worse,
some banned animal industry by-products are being exported to Asia and are being
used in feeds (authors’ personal observations). Unfortunately, very little research on
these aspects is being conducted in Asia, where the main thrust is to adopt better
management practices (BMPs) for different culture systems, with the expectation that
this would avoid extensive contamination of the final product. However, the BMPs
have not yet addressed the issue of feed quality, and it is now opportune to introduce
this through proper feed certification procedures.
8.3 Impacts on employment and food supplies for the poor
In Asia, which is not a major fishmeal producer but a major consumer (De Silva and
Hasan, 2007), two major issues are apparent: (i) Is the trash fish/low-value fish used
in the reduction industry sustainable? and, (ii) If so, what are the pros and cons of
using the fish for reduction as opposed to direct human consumption? In Asia and the
Pacific, all wild fish used in farm-made aquaculture feeds come from Asian fisheries,
most being bycatch. However, the fact is that the fish caught as bycatch affect the
supply of fish available as food, and bycatch is also of importance for employment and
income generation for the poor. The impacts of the use of fish as feeds on employment
and food for the poor in Asia are of a much lesser magnitude than elsewhere in the
world, the main reason being that much of the fishmeal used in such feeds is imported,
mainly from South America.
8.3.1 Food supplies
The great bulk of trash fish/low-value fish landings in Asia are from small-scale artisanal
fisheries and may not necessarily be in a state suitable for direct human consumption.