9465

• UCREFRP Catalog Number: 9465
• Author: Burdick, B.
• Title: Monitoring and Evaluating Various Sizes of Domestic-Reared Razorback Sucker Stocked in the Upper Colorado and Gunnison Rivers
• USFW Year: 2003.
• USFW - Doc Type: 1995-2001.
• Copyright Material: NO

A.1.). Fish were domestically-propagated and reared at different sources and sites. This included
indoor tanks at Ouray National Fish Hatchery (NFH), Utah; the 24-Rd Hatchery operated by the
FWS at Grand Junction; Valley City NFH, North Dakota; Bellvue State Fish Hatchery (SFH), Ft.
Collins, Colorado; outdoor, earthern ponds at Horsethief State Wildlife Area (SWA), near Fruita,
Colorado; and grow-out ponds at Wahweap SFH, Big Water, Utah, and in the Grand Valley of
western Colorado near Grand Junction.
Each family lot was maintained separately until they were large enough to be PIT-tagged
which was about 100 mm long. All fish produced from these controlled matings and eventually
stocked into the rivers were PIT tagged so that their genetic background could be traced.
Moreover, fish marked with PIT tags could provide specific information on stocking date and
location, as well as multiple recaptures.
Between October 1995 and October 2001, domestic-reared razorback sucker were
stocked in the Upper Colorado and Gunnison rivers at various sizes that ranged from 75-586 mm
(3-23 inches). In 1994, 45 adult razorback sucker were collected from Etter Pond, marked with
PIT tags, and surgically implanted with radio transmitters. Twenty of these fish were translocated
to the Upper Colorado River (mean TL=502 mm; range=451-534 mm) near Debeque and 25
were translocated to the Gunnison River (mean TL=492 mm; range=455-536 mm) near Delta
(Burdick and Bonar 1997). During 1999 and 2001, "excess" broodfish became available at the
Horsethief SWA ponds. These additional fish were no longer needed because sufficient numbers
of these year classes were available for broodfish and refugia. Consequently, these excess
broodfish were stocked in the Gunnison River during 1999 and 2001 (see Appendix; Table C.5.
and C.7. for length statistics).
Razorback sucker stocked into grow-out ponds were later harvested with trap nets of
various mesh sizes. Most razorback sucker harvested from grow-out ponds and those from the
24-Rd Hatchery were measured (TL, mm). In some instances when there were large numbers of
fish to stock from the 24-Rd Hatchery during one day that had already been tagged, only a
representative sub-sample of fish were measured. About every fourth razorback sucker processed
was weighed. Lengths and weights were taken from only 30 representative individuals from the
1992 year-class sub-adult razorback sucker that were reared at Wahweap SFH and later stocked
in the fall of 1997. After being PIT tagged, fish were transported from hatchery facilities or
grow-out ponds to river stocking sites using stocking trucks equipped with 250-gallon aerated
stock tanks. Upon arrival at stocking sites, razorback sucker were placed directly in riverine
habitats with the lowest possible water velocities which were usually shallow side channels or
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