9585

• UCREFRP Catalog Number: 9585
• Author: U.S. Fish and Wildlife Service.
• Title: Inland Salmonid Broodstock Handbook.
• USFW Year: n.d.
• Copyright Material: NO

SECTION 2. DISEASE
The control of fish diseases is a major concern in the culture of
all salmonid species. The efficient propagation of fish (at all
life stages) may be severely impacted by the occurrence of disease
outbreaks. While broodstock may be more resistant to diseases and
parasites than small fish by virtue of their larger size and well
developed immune system, this resistance can not be taken for
granted. When a disease outbreak does occur in a broodstock
population, it can be just as difficult to control as a similar
condition in smaller fish. Furthermore, the loss of broodstocks is
likely to result in a greater impact on program goals than is the
loss of production fish.
A basic understanding of the nature of fish diseases is essential
in order to safeguard hatchery broodstocks. Such information will
assist the culturist in both preventing and minimizing the effect
of disease outbreaks. A portion of the following discussion is
excerpted -from the Advisory Note by Kapuscinski and Gross, 1986
(1) .
Fish Diseases
Fish, like all animals, under certain conditions are subject to a
variety of diseases. Many diseases in fish are caused by
pathogens. Such organisms are generally capable of causing disease
only when the host's resistance is lowered. Common pathogenic
organisms include parasites, bacteria, fungi, and viruses. Fish
can also suffer from diseases caused by environmental and
nutritional deficiencies. A fish disease is a state of imbalance
between the fish and its environment, a condition that if not
rectified may lead to death.
Under natural conditions, fish populations seldom ekperience severe
disease outbreaks. However, when fish are crowded and reared under
the unnatural conditions of the hatchery environment, the potential
for serious disease infections is greatly increased.
Hatchery reared salmonids are subject to a wide spectrum of
diseases caused by a variety of pathogenic organisms. Complete
information on the diacrnosis identification and treatment of
s ecific salmonid diseases can be found in the manuals "Diseases of
Hatchery Fish" by Warren 1981 (2) and "Introduction to Fish
Health" by Nelson et al 1988 (3)
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