8210

• UCREFRP Catalog Number: 8210
• Author: Dodge, D. P. and C. C. Mack.
• Title: 20
• USFW Year: 1994.
• USFW - Doc Type: Direct Control of Fauna
• Copyright Material: YES

388
Management Options
is ctedited with the establishment of the first trout
farm. Remy, a professional fisherman, noticed
declining fish stocks and in 1840 decided to try to
breed trout artificially. Assisted by friends and
interested parties with influence, the success of
his operation induced the French government to
fund the construction of a large fish farm.
Following the success and publicity of Remy's
operations, trout farming started developing in
Britain, Europe and Russia. Researchers began
detailing operations, describing facilities and rec-
ognizing the need for proper management of
wild stocks, so intensive fish culture grew and
flourished worldwide.
Hatching success was low (10-20%~ in the
early operations, until in 1850 a Russian (Wrasski)
discovered the technique of dry spawning. This
method has been used ever since in salmonid
culture with good results.
Except for a greaterunderstanding of that physio-
logical entity called a `fish', modem fish culture
continues to work with the same basic factors of
growth, survival and feed conversion as did the
earliest culturists.
Fish stocking of natural waters to provide better
commercial fishing or angling became an import-
ant tool for fisheries in the mid-1800s with the
development of fish hatchery systems in Europe
and North America. Of special significaztce was
the evolution of cold-water culture techniques
that allowed the raising of very large numbers of
salmon and trout which survived long distances
and time from hatchery to planting sites. Seth
Green and Samuel Wilmot led these advances
in North America. Tremendous increases in
ranges through successful introductions of salmon
and trout (MacCrimmon ~ Marshal:l 1968;
MacCrimmon 1971 ~ resulted from the application
of their techniques.
Stocking objectives
Stocking is a method used in the management of
fish stocks as integral parts of aquatic ecosystems.
Stocking programmes must share the oljectives
of effective aquatic ecosystem management in
order to provide benefits on a sustainable basis.
Protecting and rehabilitating fish stocks
Protection of aquatic ecosystems should be a
fundamental management objective of any
fisheries programme. Fish culture can play an
important role in protecting endangered stocks
by acting as a reservoir of genetic material. The
establishment of broodstocks of selected species
and strains is an effective way of protecting
endangered fish stocks. Although there is always
a risk that artificial systems like hatcheries may
select towards a lower level of fitness, broodstock
husbandry ensures that some of the original
genetic material is always available. For example,
the Aurora trout, a unique strain of brook trout
~Salvelinus fontinalisj, was approaching extinc-
tion due to acidification of the Northern Ontario
lakes it inhabited. Hatcheries played a major role
in preserving this strain until rehabilitation of its
habitat allowed successful natural reproduction.
Rehabilitation is an important objective in
managing aquatic ecosystems where they have
been degraded. Stocking can play an important
role in rehabilitating existing native fish stocks,
providing it is used in conjunction with efforts to
restore habitat and control exploitation. Examples
include re-establishing fish stocks after major
pollution events or when destroyed spawning
habitat has been restored.
Rehabilitating fisheries with introductions
In many areas, degradation of aquatic ecosystems
has been so severe that the restoration of native
fish stocks has been deemed unfeasible. Fisheries
managers faced with this situation have often
chosen to 'rehabilitate a fishery' by using species
other than those originally present. An example
of this management technique was the introduc-
tion of Chinook and coho salmon (Oncorhynchus
tshawytscha and O. kisutchj to the Great Lakes
and its tributaries in North America. Unfor-
tunately, the introduction of these exotic species
has drastically altered the fish community struc-
ture of these water bodies, and may be a major
impediment to restoring native fish stocks when
human commitment and technological advances
enable the rehabilitation of these ecosystems.
In Africa, the primary purpose of introductions