9585

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

Prevention of Fish Diseases
Prevention of disease should be a primary objective of all
culturists. Ideally, facilities should be maintained pathogen
free. Although elimination of all pathogens is virtually
impossible, extreme care should be .exercised to prevent -the
introduction of any new pathogenic organisms. Only stocks, that
have undergone a complete disease history evaluation and have been
classified specific pathogen free (see Fish Health Policy and Fish
Health Policy Implementation Guidlelines, Appendices A and B)
should be considered for introduction to any broodstock facility.
Water quality parameters should always be maintained within
suggested limits (Tables 2A, 2B, 2C, Wedemeyer, 1981 (4)). The
importance of minimizing environmental and management stress to
fish stocks as it relates to the prevention of disease cannot be
overemphasized.
Warning Signs Of Disease
In spite of the best preventative efforts, diseases still occur.
It is vital to treatment and control that diseases are detected as
soon as possible. The best method to detect a disease at its .onset
is by the close observation of fish during feeding. If any of the
following conditions are observed, a disease outbreak should be
suspected and immediate treatment recommended:.
Behavioral Signs
-- Failure to feed in a normal fashion
-- Flashing (turning on their sides)
-- Riding "high" in the water
-- Rubbing on the bottom
-- Gathering around the water inflow
-- Reduced vitality (lethargic)
-- Abnormal distribution (scattered
-- Gasping at the sur-face
Physical Signs
-- Blistered areas
-- Swollen abdomen
-- "Pop-eye"
throughout rearing unit)
Hemorrhaged areas on fin bases or eyes
Discoloration and/or erosion of body parts
Excessive mucus production
Fungus growths
Abnormal growths on body parts
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