Environmental Engineering Reference
In-Depth Information
ecosystems. As to whether stocks of feed fish are being managed sustainably, there
is, as yet, no definitive answer. FAO classifies most of them as 'fully fished' rather
than overfished and this does imply sustainability. In an analysis of two important
species, the Peruvian anchovy and the European sandeel, Huntington et al. (2004)
could not determine whether the fisheries were being exploited sustainably or not.
Their conclusion reflected a lack of knowledge about natural processes but there
were no worrying trends in catch statistics to suggest that fishing pressure was
damaging stocks.
5.13.3 Antibiotic residues
Although most countries have banned chloramphenicol and nitrofuran antibiotics
from animal food production due to their toxicity to humans, traces of the drugs have
been detected in shrimp and other aquaculture products (Somjetlerdcharoen 2002).
Chloramphenicol can cause potentially fatal aplastic anaemia and leukaemia, and
nitrofurans are carcinogenic (IARC 1974, 1997). Therefore, GAA fully supports
regulations that control the drugs to assure wholesome foods for consumers. At
issue in the current debate on antibiotic residues is the distinction between detection
and toxicity. Advancing analytical technology is allowing detection of substances at
ever-diminishing levels. For example, heavy metals, pesticides and carcinogens can
be highly toxic, yet are found in virtually all wholesome foods at trace levels. Studies
have shown that low levels are likely to be innocuous. With increasing analytical
capability, it is unrealistic to expect foods to be always free of any detectable level
of hazardous substances.
Meanwhile, the use of antibiotics in aquaculture, already minimal, is steadily
declining as farmers come to recognise that these chemicals are expensive and
only offer very short-lived or non-existent benefits to a crop (Asche & Tveteras
2006). Improvements in technology, husbandry practice, nutrition, water-quality
management and general health management procedures are making antibiotic
therapy increasingly redundant. And domestication and the development of new
breeds of fish and shellfish are enabling selection for strains with characteristics
including innate disease resistance, so reducing the need for the use of antibiotics.
5.13.4 Trade issues
The rapid growth in aquaculture production and increasing international trade in
seafood are bringing important changes to established markets for fish and shell-
fish. Some fisheries and aquaculture industries in rich countries are coming under
pressure from cheaper producers in developing nations. As a result they are in-
creasingly calling for protectionist measures to shield themselves from the effects
of globalisation. The EU applies tariffs to most seafood imports and the Department
of Commerce in the US is applying anti-dumping duties on Chinese supplies of
farmed freshwater crayfish and Vietnamese supplies of farmed catfish, and it is now
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