International Council for the Exploration
of the Sea (ICES) led to the formulation
of related Codes of Practice and protocols
(EIFAC 1984; FA0 1986; Turner 19881,
which have been adopted by EIFAC
member countries and which have been
reviewed subsequently by FA0 regional
fisheries commissions such as the Com-
mission for Inland Fisheries of Latin
America and the Caribbean (COPESCAL),
the Committee for Inland Fisheries of
Africa (CIFA) and the Indo-Pacific Fish-
ery Commission (IPFC) (see also IPFC
1 988a, l988b; FA0 1990; FA0 1991). Many
countrieshave enactedlegislation to regu-
late and control the movement of eggs,
larvaeljuveniles and adult stages of exotic
fish species, often combined with compul-
sory certification of stocks to be free of
certain diseases and banning of all move-
ments of diseased stocks (Van Houtte et
al. 1989).
Good husbandry, particularly efficient
use of feeds and fertilizers, is essential to
minimize the harmful effects of effluents
from fish farms. Feed formulation is of
great importance. Feeding rates can be
optimized in order to avoid overfeeding
(New 1987). Poor processing and storage
of feed results in losses and deteriorative
changes, including microbial contamina-
tion and content of harmful substances,
e.g., solvent residues, aflatoxin, botulinum
toxin, therapeutic drugs, etc. (Tacon 1987).
Extruded diets may help to improve feed
quality and digestibility thus reducing
pollution, but the extrusion technology is
costly and complex (Clarke 1990).
Fish farm effluents can also be treated
to reduce their impact. However, high
flow rates and dilute concentrations of
pollutants in such effluent pose problems.
Treatment facilities must be eff~ient, yet
economically feasible to install and to
operate. Treatment technologies for in-
tensive aquaculture are being developed
in industrialized countries based on sedi-
mentation, decantation, biological oxida-
tion and filtration (Petit andMaurel1983).
Often these techniques are designed for
'%igh-tech" systems (Makinen et a1.1988).
Economic constraints in production and
operating costs often make the treatment
of fish farm wastes dmcult to support
(Muir 1982), particularly in developing
countries.
Integration of aquaculture with other
activities (agriculture, industrial and
urban use of water) is likely to be the most
effective means of development, by shar-
ing water use or enhancing its value
sufficiently to allow investment in im-
proved water supply or treatment (Muir
and Beveridge 1987).Aquaculture Legislation
and Conservation
of Freshwater EcosystemsAccording to Howarth (1990),
aquaculture ought to be environmentally
regulated for its owninterest. Aquaculture
depends upon a good aquatic environment.
It is particularly vulnerable to excessive
abstraction and water contamination from
a range of industrial, agricultural and
domestic sources. However, aquaculture
is also susceptible to risks of self-pollution.
Hence, its own interests justify measures
directed towards the regulation of water
abstraction, and the prevention of unac-
ceptable contamination, including pollu-
tion and emission of potentially harmful
substances from fish farms. Likewise, the
restriction offishmovementsis sometimes
required to avoid the spread of diseases
between farmed populations, and from
farmed populations into the wild and vice
versa.
Legislative and administrative meas-
ures ~.iming at the environmental compat-
ibility of the various aquaculture practices
should be considered within the broader
legislative context governingaquaculture.
Most developing countries have little or