Environment and aquaculture in developing countries

Table 6. Developing-country aquaculture systems: environmental impact and benefits for producers.
Extensive systems are defined as havingno feedorfcrtilizer inputs; semi-intensive systems as havingsome
feed andor fertilizer inputs; and intensive systems as being mainly reliant on external feed inputs. The
possible consequences al exotic breed transfern apply to all systems listed here (Pullin 1989). Enhanced
fisheries are not included here because of the general lack of developing-country examples.

System Environmental Impct Benefits

EXTENSIVE

1. Seaweed culture May o~cupy lonnerly pristine reefs;
   rough weather losses; market
   competition; con~ictd~ilures.
   mid disruption

Income; employment;

foreign ahange

2. Coastal bivalve culture (mussels.
   oysters, clams, cockles)

Public haallh risks and consumer

resistance (microbial diseases,

red tides, industrial pollution): rough

weather lomas; wed shortages;

market competition espdnlly Tor

export produce; hilures, wial

disruplion

Income; employment;

foreign exchange: directly

improved nutrition

3. Coastal fishpands (mullets.
   milkfish, shrimps, tilapias)

Destruction of ecosystems, especially

mangroves; increasin&Iy noncomptitiva

with more intensive oystems; non-

sustainable with high population

growth; conflictdfailuros. social

disruption

Income, employment,

foreign exchange (shrimp):

directly improved nutrition

4. Pen and cage culture in eutrophic
   waters and/or on rich benthos
   (carps, catfish, milkfiah,
   tilapias)

Exclusion of traditional fishers:

navimtional hazards: conflicts.

Income; employment; directly

improved nutrition

mci; disruption; management

difficulties; wood consumption

1. Fresh- and brackishwater ponds
   (rhrimpm and prawna; carpa, catfiah,
   milkhh, mullets, tilapias)

Freshwater: health risks to farm Income; employment; foreign

axchange (shrimps and

prawna) directly improved

nutrition

workern hm waterborne diseuses.

Brackishwater: unlinization/acid-

LBcation of soildaauirers. Both.

market competition, especially for

evporl produce; feed and fertilizer

availabllity/prices: codictdliluras,

Boeial diuruptlon

Income; employment; directly

improved nutrition: synermstic

2. Integrated agriculture-aquaculture
   (ricedsh; 1ivestocWpoultry-Rsh;
   venetables-fish and all

An fwshwater above, plus possible

consumer re~i~tance to excreta-fed

produce; competition from other users of

inputs such as livestock mreta snd

cereal brans; taric rubstances in

liveslock feeds (e.g.. heavy metals) may

accumulaie in pond sediments and fish:

pesticides may accumulate in Kah

int&ctions betweencrop:

combinations of these) livestock.. ve~etablt - and

fish componenls:

recycleu on-lam reaidues

and olher cheap resourceo

3. Sewage-fish culture (waste
   treatment wnds: lalrine wantan and

Possible health riake to krm workers and

consumers: consumer resishnce lo produce

Income; employment; directly

improved nutrition; turn. waste

disposal liabilities into

productive assetu

septage u&d as pond inputa;

fish cages in wastewater chsnnels)

4. Cage and pen culture,
   especially in eutrophic
   waters or on rich benthos
   (carpupa, catfish, milkhh,
   tilapian)

An etensive cage and pen systems above Income; employment; directly

improved nptrition

mntinued