696
Disinfection/Water Treatments
Apart from the use of antibiotics and related compounds, which are actively discouraged from use in any nonmedical situation in many countries, the application of
other chemicals to water as disinfectants is effective for disease control. Such chemicals include benzalkonium chloride, chloramine B and T, chlorine, formalin and
iodophors.
Another approach is to alter (increase or decrease, according to the season) the
temperature of water within fi sh holding facilities, which may be achieved by altering the water fl ow, providing shading, or actively heating/cooling as appropriate.
Genetically Resistant Stock
This is a topic worthy of greater attention, insofar as there are numerous observations, which point to the value of genetically resistant strains or selective breeding
for reducing the problems of disease. As a word of caution, however, comparative
studies need to be carefully controlled so that meaningful results are obtained. In
any comparison, the age, size and relative condition of the animals need to be standardised. Nevertheless, there has been prolonged interest in breeding diseaseresistant fi sh. It is obvious that the breeding of disease-resistant fi sh may be a
valuable addition in the armoury of disease control in aquaculture. However, in fi sh
farming where more than one disease is prevalent, it is not necessarily the case that
a fi sh strain which is resistant to one disease, would similarly show resistance to
others. Nevertheless, we consider that disease-resistant strains of fi sh have potential
for areas in which diseases are enzootic. Further effort is clearly required to bring
the concept to fruition. One overriding concern is the public misconception of the
risks associated with GMOs, which is profound in some countries, particularly in
Western Europe, but less so or non-existent in others.
Adequate Diets/Dietary Supplements/Non-Specifi c
Immunostimulants
An area of comparatively recent interest is that of dietary infl uence on fi sh health.
Could some essential nutrients be lacking, or other compounds be present in dangerous excess? A mass of published work has pointed to the benefi t to health, welfare and growth of the addition of any of a wide range of natural products to fi sh
feed. For example, Ketola ( 1983 ) highlighted a requirement for arginine and lysine
by rainbow trout fry, with fi n erosion resulting from a defi ciency of lysine. The list
14 Control
Disinfection/Water Treatments
Apart from the use of antibiotics and related compounds, which are actively discouraged from use in any nonmedical situation in many countries, the application of
other chemicals to water as disinfectants is effective for disease control. Such chemicals include benzalkonium chloride, chloramine B and T, chlorine, formalin and
iodophors.
Another approach is to alter (increase or decrease, according to the season) the
temperature of water within fi sh holding facilities, which may be achieved by altering the water fl ow, providing shading, or actively heating/cooling as appropriate.
Genetically Resistant Stock
This is a topic worthy of greater attention, insofar as there are numerous observations, which point to the value of genetically resistant strains or selective breeding
for reducing the problems of disease. As a word of caution, however, comparative
studies need to be carefully controlled so that meaningful results are obtained. In
any comparison, the age, size and relative condition of the animals need to be standardised. Nevertheless, there has been prolonged interest in breeding diseaseresistant fi sh. It is obvious that the breeding of disease-resistant fi sh may be a
valuable addition in the armoury of disease control in aquaculture. However, in fi sh
farming where more than one disease is prevalent, it is not necessarily the case that
a fi sh strain which is resistant to one disease, would similarly show resistance to
others. Nevertheless, we consider that disease-resistant strains of fi sh have potential
for areas in which diseases are enzootic. Further effort is clearly required to bring
the concept to fruition. One overriding concern is the public misconception of the
risks associated with GMOs, which is profound in some countries, particularly in
Western Europe, but less so or non-existent in others.
Adequate Diets/Dietary Supplements/Non-Specifi c
Immunostimulants
An area of comparatively recent interest is that of dietary infl uence on fi sh health.
Could some essential nutrients be lacking, or other compounds be present in dangerous excess? A mass of published work has pointed to the benefi t to health, welfare and growth of the addition of any of a wide range of natural products to fi sh
feed. For example, Ketola ( 1983 ) highlighted a requirement for arginine and lysine
by rainbow trout fry, with fi n erosion resulting from a defi ciency of lysine. The list
14 Control