7327

• UCREFRP Catalog Number: 7327
• Author: Johnson, J. E.
• Title: Status of Endangered and Threatened Fish Species in Colorado.
• USFW Year: 1976.
• USFW - Doc Type: T/N 280,
• Copyright Material: NO

2. General Description - Head and body elongated. A sharp-
edged keel developed in adults from eyes to dorsal fin.
Lateral line scales moderately small, 68 to 80 in number;
scales often absent from, or deeply embedded in, skin of
anterior margin of predorsal keel. Dorsal fin relatively
long, with 13 to 16, usually 14 or 15, fin-rays. Gill rakers
slender and numerous, 44 to 50 on the first arch. Color
olivaceous to brownish-black above, lighter below (often
yellow). Sides with brown or pinkish to reddish-brown stripes.
Dorsal fin dark; anal fin yellow; caudal fin light yellow-
brown. Breeding males black or dark brown on top and upper
sides, orange laterally, and bright yellow on belly (Minckley,
1973). One of our largest native suckers, the humpback once
reached a length of three feet and a weight of 16 pounds.
3. Present Distribution and Status (Fig. V) - Extirpated from
much of the lower Colorado River drainage, but maintaining
populations in several main stream reservoirs (Mohave, Havasu
and perhaps Mead and Martinez). Although there are reports
of reproduction in these reservoirs, humpback sucker concen-
trations in all reservoirs should be viewed warily. For
example, the population in Saguaro Lake (Salt River, Arizona)
went from an annual commercial harvest of six tons in 1949
to not a single fish in the lake by 1965 (Minckley, 1973).
In Colorado, populations have been reported from the Colorado
River above and below Grand Junction, the Yampa River below
Craig and the White River below the inflow of Piceance Creek.
None have been found in recent years in the Dolores and
Green rivers, but further collections should be made.
4. Existing Management Plans - Adult fish were artificially
spawned at Willow Beach National Fish Hatchery (Arizona)
in spring, 1974, and several thousand offspring are presently
being reared. Plans are for these fish to be released in
Arizona or Colorado waters. Because of its undetermined
status on the federal endangered species list and apparent
abundance in certain localities, less work is being initiated
on this species. Thus, even though it is included on the
State's endangered species list, no management plans appear
in the November, 1974 Endangered Animals Cooperative Agree-
ment Application. However, the lower Colorado River Drainage
System Endangered Fishes Recovery Team is publicizing the
rarity of the sucker, asking anglers to return their catch
and then report it to local game and fish agencies.
5. BIM Interest - Similar to Colorado squawfish.
16