7315

• UCREFRP Catalog Number: 7315
• Author: Colorado Water Conservation Board.
• Title: State of Colorado Hatchery Feasibility Study for Endangered Fishes of the Colorado River Basin, Vols. 1 & 2.
• USFW Year: 1993.
• USFW - Doc Type: \
• Copyright Material: NO

.

.

.

REFERENCE NUMBER:

018

CITATION:

Inslee, T.D. 1981. Spawning of razorback suckers. Pages 145-157 In
W.H. Miller, JJ. Valentine, and D.L. Archer. (cds.) Colorado River
Fishery Project Final Repon: Pan 3, Contract ReportS. U.S. Fish
and Wildlife Service, Bureau of Reclamation., Salt Lake City, Utah.

SPECIES AND LIFE STAGE:

RZ. RZ_EGG, RZ_LARV AE, RZ_ADULT

TOPICS:

Production, Culture Techniques, Diet

KEYWORDS:

RAZORBACK SUCKER, SPAWNING, HORMONE INJECTION,
HATCHlNG, FUNGUS, FEEDING

SUMMARY: Razorback suckers (136) were transferred from Lake Mohave to Dexter NationalFlSh
Hatchery. Four spawning methods were tried: pond spawning, spawning in flow through
ponds, circuJar tank spawning, and holding house tank spawning. Best results were found using
6-foot circular t.anks. The bottoms of the tanks were lined with 112 to 3 inch rocks and filled
to a depth of 22 inches. Well water, averaging 620F, was pumped at 10 Umin and aimed at
a 450 angle to produce a circular flow.

Hormone injections of 500 IU chorionic gonadotropin and 2 mg/lb carp pituitary were tried
on female fish. Injections of 2 mg carp pituitary per pound of female brood fish were most
sua:essful.

Eggs were incubated utilizing five methods: Mcdonald jars; in the circuJar tank on rocks after
natural spawning; in a circular tank after stripping; on a fine-mesh net suspended in holding
house tank; and a Heath incubator. Hatching results were best in the Heath incubators.

Egg fungus was treated with formalin solution. It was found that viable eggs can be treated
with a solution as strong as 1:75 for 10 minutes. Fungi can be killed or retarded with 1:200
formalin for 10 miD. Recommended treatment is a constant flow concentration of 1:100 for 10
minutes on the 2nd and early on the forth day after hatching.

Fry were offered a diet of trout slaner four times daily for the first 17 days. The fish were
then moved to a 0.1 acre rearing pond that had developed a zooplankton bloom. The plankton
bloom was started by addition of 100 pounds of manure and 80 pounds of 18-46-0 feni1izer to
the bottom of the pond before filling.

A-IS