Environment and aquaculture in developing countries

A number of studies have shown that
wild fish often congregate in the vicinity of
marine cage farms. In addition, the
presence of ~ish farms may influence the
population structure and act as areas for
recruitment because of the additional
supply of food (Henriksson 1991 ). The
significance ofthese findings is notknown.
The potential forthe transfer ofgenetic
material from escaped farmed fish to wild
fish has recently caused considerable
debate (NASCO 1989). It has been
suggested that breeding programs in
aquaculture have resulted in significant
differences between farmed and wild fish
(Cross 1991). A consequence of
interbreedingbetween significant numbers
of escaped farmed fish and wild fish could
result in the latter losing important traits
and becoming less well adapted. It is clear
that large numbers offarmed fish do escape
and enter rivers. Gudjonsson (1991) found
that 30% of the fish caught in the River
Ellidaar in Iceland were of farm origin.
Furthermore, it has been shown that
genetic material can pass fromfarmedfish
into wild populations (Crozier, in press).
At the present time, the ecological
significance of such transfers is not known,
but in recognition of the potential problem,
several countries have established
regulations excluding development from
important river estuaries.

Social and Economic Effects of the

Development of Intensive Cage

Culture

The potential social and economic

benefits of aquaculture development are

clear. In Scotland, it was estimated that in

1990 approximately 1,600 people were in

full-time employment in aquaculture

(mainly finfish farming). Despite this,

expansion of fish farming in Scotland has

brought this industry into conflict with

other users ofaquatic resources. This trend

of increasing conflict with other forms of

coastal development has also been observed

in southern Europe and North America.

Some of the more obvious potential

conflicts are listed in Table 2. Only a few

attempts have been made to assess the

effects of aquaculture development on

tourism (Anon. 1988; Sargeant 1990) and

recreation (McNab et al. 1987). In general

however, such studies are subjective and

it is difficult to obtain a clear understanding

of the effects of aquaculture development

on other users of the coastal environment.

In recognition of some of the problems

which have arisen, fish farming

associations have produced codes of

practice. The Scottish Salmon Growers'

Association has produced a voluntary code

for avoidingvisual impact ofdevelopments

on the landscape. Such codes of practice

Table 2. A summary of some of the main social issue8 associated with aquaculture development.

Competition for space

Traditional fishing

Navigation

Anchorages and marinas for recreational boating

Different forms of aquaculture and between aquaculture and other industries (e.g., wood pulp).

Amenity, recreation and tourism

Visual impact and loss of wilderness aspects of the countryside

Restriction on access toland, foreshore andinshore areas whichmay affect outdoor activities(watersports)

and harvesting of shellfish for nonmmmercial purposes

Reduction in amenity value of freshwater for recreational fishing

Reduction in the value of property