Conservation and Sustainable Use of the Biosphere - WBGU

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Conservation and Sustainable Use of the Biosphere - WBGU

168 E Diversity of landscapes and ecosystems

the relevant German Federal Ministry. Implementation

of these should be moved forward quickly.

Finally, the EU-wide implementation of the

amended Control Regulation on the Monitoring of

Fisheries within and outside EU waters that entered

into force on July 1, 1999 should be promoted. In particular,

the objectives of the increased openness of

fisheries monitoring in the individual member states,

the improvement of cooperation between member

states with regard to controls and the better control

of third country ships can help to achieve higher

acceptance among fishermen by reinforcing equal

treatment.

E 3.4.2

Aquaculture

When obtaining food from breeding systems, a distinction

must be made between industrially-operated

intensive and extensive aquaculture, the latter of

which is frequently combined with agricultural production.

Whereas industrial aquaculture primarily

produces luxury products such as salmon, lobster or

prawns for export, extensive aquaculture integrated

in small farms in developing countries makes a contribution

towards local and regional food security

(WBGU, 1998a). In aquaculture, there is increasing

use of transgenic fish, which are equipped with additional

growth hormones to increase fish production.

This leads to shifts in the population composition,

changes in behaviour and changes in the food web.

The use of quantities of growth hormone that is alien

to the species question in predatory fish species is

considered to be especially critical (UBA, personal

communication).The following three case studies are

designed to reveal the scope and problems of the various

aquaculture systems. These are cases in which

aquaculture has already reached a relatively

advanced state, so that experience gained thus far can

be used to derive approaches for increasing efficiency

and for the social and environmental compatibility

of aquaculture.

E 3.4.2.1

Integrated carp breeding as an example of

freshwater aquaculture

There are many years of experience with the cultivation

of carp in China, India and other south-east

Asian countries in particular. The distinguishing

characteristic of integrated carp aquaculture is its

combination with the most varied plant crops (sugar

cane, bamboo, fruit trees, flowers), depending on the

local conditions, and frequently also an internal

waste recovery system. The integrated breeding of

herbivorous species such as carp also offers small

farmers economic advantages thanks to relatively

low technical requirements for production. The Chinese

and Indian carps are usually kept in mixed crops

of 2–3 species drawing on complementary food spectrums,

which allows more efficient use of the available

food and thus a corresponding increase in fish

yields.

In India, Indonesia and Bangladesh many naturally

hatched young larvae are still being used for

rearing, whereas in China and Europe the brood

material is produced artificially. The stocking rate of

carp ponds fluctuates between 4,000 and 5,000 larvae

ha -1 with a length of 2.5–5cm or 2,000–3,000 larvae ha -1

with a length of 5–10cm. The rearing time to achieve

a fish weighing 1–1.2kg is around two years in

Europe. In the tropics, fish are harvested with a

weight of 0.6–1kg, which need only one year for their

development.

Fertilizers are added to the fish ponds in order to

maximize the yields, with slurry and compost being

primarily used in Asia. However, this harbours the

risk of infections through bacteria, fungi and viruses.

The mortality of grass carp can be 70–90 per cent in

China. In addition to diseases, parasite infestation is

widespread.

E 3.4.2.2

Shrimp farming as an example of industrial

aquaculture of crustaceans

Between 1982 and 1994 the annual production of

prawns (shrimps) from aquaculture rose from

100,000 to 900,000 tonnes. Production takes place

mainly in developing and newly-industrializing countries

(eg Philippines, Thailand, Indonesia, China,

India and Ecuador) and is largely exported to industrialized

countries as a cash crop. In south-east Asia,

1.2 million ha of coastal land areas are currently

being used for ponds; in the western hemisphere this

figure is around 0.2 million ha.

In the Latin American countries in particular, the

larval material is largely obtained from natural

stocks because they are considered to have higher

resistance to infection. By contrast, the majority of

prawns in south-east Asia are reared from larvae produced

by humans. They are mainly reared in ponds

created in salt marshes, wetlands or mangroves. But

these are areas traditionally used by farmers (for

rice) and inland fishermen, meaning that in many

places the interests of farmers, fishermen and prawn

breeders collide.

A distinction can be made between three rearing

models: in the extensive or traditional method, the

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