7406

• UCREFRP Catalog Number: 7406
• Author: Bestgen, K. R.
• Title: Status Review of the Razorback Sucker,
• USFW Year: 1990.
• Copyright Material: NO

In reservoirs, razorback sucker larvae may be susceptible to
involuntary movement caused by wave action and currents in near-
shore habitats but this has not been studied. Larvae in
reservoirs moved from the substrate into the water column,
especially at night when attracted to a strong, artificial surface
light (Bozek et al. 1984). Larvae were not observed by divers
during the day but were common in the same areas at night.
Hatchery-produced razorback sucker juveniles introduced into
some streams in the Gila and Verde river drainages showed a marked
tendency for downstream dispersal (Brooks 1985, Marsh 1987). Mass
downstream movements at night were documented while very little
upstream movement was noted.
Springtime movements of adult razorback suckers have been
described from observations, tag-recapture data, and
radiotelemetry. Early observers described "springtime runs" of
razorback suckers and other large-river fishes from mainstream
environments into smaller tributaries, presumably for spawning
(Minckley 1973). Other observers recorded springtime movements
associated with spawning in lentic systems from deeper offshore
areas into shallow water zones adjacent to rocky shorelines
_ (Douglas 1952, Jonez and Sumner 1954, Minckley 1983). The annual
springtime appearance of razorback suckers below diversions (Kidd
1977), in gravel pits (McAda and Wydoski 1980, Valdez et al.
1982a), and downstream of larger dams also suggested movements
associated with spawning (Mueller 1989).
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