designed for self-consumption, is likely to
be pursued after the completion of exter-
nal assistance. Not enough attention has
been given to special credit facilities for
small-scale aquaculturists on terms and
conditions which address their weak eco-
nomic conditions and particular needs.
Integrated agriculture-aquaculture is
still evolving as a technology applicable
in many developing and industrialized
countries. Environmentally friendly, model
integrated farming systems, developed on
research stations are rarely adopted be-
cause of their complexity. Very few Farm-
ing Systems Research and Extension
(FSRE) initiatives attract sufficient
adopters to show any real impact.
Why are FSRE and agroecosystem tools
so little used in systems that incorporate
aquaculture? The first and most impor-
tant reason is the institutional structure
in which agricultural research and devel-
opment is conducted. FSRE requires ss-
cia1 scientists to work alongside biologists.
Such interdisciplinary teams require all
members to have a working knowledge of
the other disciplines but educational pro-
grams rarely offer appropriate courses
(Edwards et al. 1988). Agroecosystem
analysis and the new farming systems it
inspires require integration of crops, live-
stock, fish and forestry but these coa-
modities are often separated into different
departments, ministries and research
institutes at national and international
levels. Institutional barriers inhibit the
growth of expertise, the flow of funds and
the use of FSRE and agroecosystem tools
(Lightfoot 1990).
Integrated aquaculture, if developed,
can become a very useful tool for water
management. Run-offfrom the catchment
area and the nutrients it carries can be
stored in fishponds and used for other
purposes such as livestock, irrigation and
domestic consumption. Ponds can raise or
sustain the local water table thus facili-
tating the excavation of shallow wells.
Nutrients in the run-off from small basins
can be trapped in fishponds where animal
excreta and plant residues can also be
recycled into proteins (Pretto 1989).Aquaculture in Reservoirs
and LakesFreshwater aquaculture in lakes and
reservoirs can have all the abovementioned
negative impacts, includingeutrophication
through the organic fallout from fish cages,
impairment of esthetic qualities and dis-
ruption of resident fish stocks.
The main constr~int to the develop-
ment of this sector is the lack of fisheries
management plans for reservoirs. For
example, in Venezuela, "the management
of these water bodies constitutes a conflict
area among different government organi-
zations which share legal competence"
(translated from Novoa, in press). Moreo-
ver, many such waterbodies do not have
even the minimum required infrastruc-
ture for exploitation and management of
their fisheries, and physical and biological
limitations prevent, in many cases, any
developme~:t. Very often, long distances
to markets and a lack of functional roads
discourage attempts to develop activities.
Despite these limitations, culture-based
fisheries in reservoirs and lakes have a
significant potential, especially in regions
such as Latin America. This potential has
been only partially realized but affords
examples of successful experiences of
relevance to other parts of the world.
Virtually all the large drainage basins
in Latin America are progressively becom-
ing regulated by dams and will ultimately
form chains of reservoirs if existing plans
are completed. Out of a tctal of 182 dams
scheduled for the Parand River sub-basin
(Argentina, Paraguay, Brazil), 121 are
already in operation or under construc-
tion. Thirty-two dams are being built in
the Magdalena River basin which will also