7809

• UCREFRP Catalog Number: 7809
• Author: Wydoski, R. S.
• Title: Responses of Trout Populations to Alterations in Aquatic Environments
• USFW Year: 1978.
• USFW - Doc Type: A Review, reprinted from John R. Moring, ed., Proceedings of the Wild Trout - Catchable Trout Symposium.
• Copyright Material: NO

- NATURAL

~ - GRAZED

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+ 3361:

+ 268%

200 100
BIOMASS (kg/ha)

o 1 2 3 4 5
POPULATION (no.X1,OOO/ha)

Figure 2. The effect of livestock grazing on brown trout populations and biomass in
Rock Creek, Montana. (Data from Table 6; Marcuson 1977)

1971). Flooding has been demonstrated to
drastically reauce trout populations, espe-
cially young of the year (Hansen and Waters
1974; Hoopes 1975; Seegrist and Gard 1974).

1800's without proper planning, engineering
or financing (Little 1973). This report also
indicated that 56,315 kID (35,000 mil of
stream channels have been modified by small
watershed programs since 1940. The chan-
nels that were modified by larger federal
flood control and navigation projects of
the Corps of Engineers and the Bureau of
Reclamation are not included in these values.

The American public questioned the use
of public funds for stream channelization in
the early 1970's because of the detrimental
impacts to the environment (Cicchetti et al.
1973; U. S. House of Representatives 1973).
As a result, several comprehensive reviews
were made of the environmental impacts of
stream alterations (Little 1973; u.s. House
of Representatives 1973). A report to the
u.s. Council on Environmental Quality indi-
cated that at least 321,000 kilometers (200,-
O~ miles) of strea~s had been developed or
modified in the United States since the early

The impacts of stream channelization
on aquatic systems has been documented by
Baldes (1973), Barstow (1971), Bayles~ and
Smith (1967), Beland (1953), Cederholm and
Koski (1977), Choate (1972), Corning et al.
(1975), Duvel et al. (1976), Etnier (1972),
Gebhards (1970), Gillette (1972), Henegar
(1971), Irizarry (1969), Saunders and Smith

AGRICULTURE

RAILROAD

ROAD

INDUSTRY

o

10 20
AL TERED STREAt1 CHANNELS

30
(% of Total)

40

Figure 3.
streams.

Stream channel alterations bv man-induced activities in thirteen Montana
(From Peters and Alvord 1964)

60