9585

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

Fish Health Monitoring
The purpose of a fish health monitoring program is to obtain
pertinent information as to the relative health status of fish
stocks. Such information is collected on a routine basis, rather
than only after a disease outbreak is already suspected. A well
designed fish, health monitoring program should- enhance the
efficiency of overall hatchery operations, as well as minimize the
occurrence and impact of fish diseases. An excellent ,guide to
establishing an effective fish health monitoring program is the
work of Meyer et al., 1983 (5).
Ideally, every hatchery should have at least one person trained in
basic fish health monitoring practices. Such training includes
basic knowledge of disease diagnosis, therapy, control, and
prevention, as well as techniques for the collection, preservation,
and shipment of samples for laboratory analysis. Personnel trained
in basic fish health management provide an invaluable asset for
planning and conducting a viable fish health monitoring program.
Procedures involved in the diagnosis of many common fish diseases
are neither time consuming nor complicated. Bacterial gill
disease, perhaps the most common and debilitating disease. of
hatchery fish, can usually be detected by an individual with a
minimum of instruction and access to a suitable microscope.
Prompt, on-site detection and treatment of fish diseases is the
best methodology to maintain .fish quality and minimize losses.
Mortality Patterns
Mortality rates of fish should be carefully monitored and recorded
daily. Mortality data can indicate the trend of the disease and
provide important clues as to the causative agent(s). The
relationship between cumulative mortality and time (days) is
illustrated in Figure 2B (Meyer et al., 1983 (5)). Line (A)
represents mortality indicative of a severe environmental failure
(e.g. low dissolved oxygen or a toxic chemical. Line (B)
represents a mortality pattern indicative of a severe disease
outbreak. Line (C) mortality is indicative of a chronic or
persistent disease infection. Diagnostic laboratories can use this
information to help distinguish between infectious and other types
of disease.
Disease Diagnosis
In many cases, fish culturists will require the assistance of a
trained pathologist to diagnose and recommend treatment. If an
infectious disease outbreak is suspected, a trained disease
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