7434

• UCREFRP Catalog Number: 7434
• Author: Edwards, E. A., G. Gebhart and O.E. Maughan.
• Title: Habitat Suitability Information
• USFW Year: 1983.
• USFW - Doc Type: Smallmouth Bass.
• Copyright Material: NO

Reproduction
Smallmouth bass spawn in spring, usually mid-April to July (Watson 1955;
Henderson and Foster 1957; Harlan and Speaker 1969; Turner and MacCrimmon
1970; Smitherman and Ramsey 1972; Neves 1975; Pflieger 1975), depending on
geographical location and water temperature. Cleary (1956) observed a 45 day
post-nesting period for smallmouth spawning in Iowa streams.
Smallmouth bass spawn on rocky lake shoals, river shallows, or backwaters
or move into creeks or tributaries to- spawn (Harrison 1954; Webster 1954;
Cleary 1956; Sanderson 1958; Harlan and Speaker 1969; Coble 1975; Clancey
1980). Smallmouth bass spawned in warm sloughs or backwater areas bordering
the Columbia River (Montgomery et al. 1980). The species requires a clean
stone, rock, or gravel substrate for spawning (Robbins and MacCrimmon 1974).
Studies show that the habitat condition during spawning is the most important
factor for year class strength in smallmouth bass (Clancey 1980).
Nest building and spawning occur when the water temperature is
12.8-21.0° C (Turner and MacCrimmon 1970; Scott and Crossman 1973; Shuter
et al. 1980), but most activity occurs at or above 15° C (Henderson and Foster
1957; Latta 1963; Harlan and Speaker 1969; Coble 1975; Shuter et al. 1980).
Specific Habitat Requirements
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Optimum riverine habitat is characterized by cool, clear, midorder streams
> 10.5 m wide (Carlander 1977) with abundant shade and cover (Larimore et al. '
1952) and deep pools, moderate current, and a gravel or rubble substrate
(Sanderson 1958; Robbins and MacCrimmon 1974; Coble 1975; Pflieger 1975).
Streams with gradients of 0.75-4.70 m/km, that provide alternating pools and
riffles, support the largest stream populations of smallmouth bass (Trautman
1942; Hallam 1959; Robbins and MacCrimmon 1974; Coble 1975; Funk and Pflieger
1975). Standing crop is generally largest in pools deeper than 1.2 m (Robbins
and MacCrimmon 1974; Paragamian 1979; Clancey 1980).
Growth of smallmouth bass is faster in lakes and reservoirs than in
rivers (Robbins and MacCrimmon 1974). Optimum lacustrine habitat is char-
acterized by large, clear lakes and reservoirs with an average depth greater
than 9 m with rocky shoals (Turner and MacCrimmon 1970; Coble 1975; Miller
1975; Pflieger 1975). Large concentrations of smallmouth bass occurred over a
broken rock and boulder substrate with a large amount of interstitial space in
the Tongue River Reservoir in Montana (Penkal and Gregory 1980). No bass were
found over a rounded rock substrate or sand in the Snake River (Munther 1970).
Although smallmouth are able to live in small ponds (Bennett 1965; Buck and
Thoits 1970; Coble 1975), populations are more successful in larger lakes and
reservoirs (Jenkins 1975). Smallmouth are found almost exclusively in the
epilimnion during summer stratification in northeastern Wisconsin and Ontario
(Hile and Juday 1941; Turner and MacCrimmon 1970), yet frequent depths up to
12 m in all seasons in northern New York (Webster 1954).
Smallmouth bass exhibit strong, cover-seeking behavior and prefer protec-
tion from light in all life stages (Coble 1975; Miller 1975). Deep, dark
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