9463

• UCREFRP Catalog Number: 9463
• Author: Badame, P. V. and J. M. Hudson.
• Title: Reintroduction and Monitoring of Hatchery-reared Bonytail in the Colorado and Green Rivers; 1996-2001.
• USFW Year: 2001.
• USFW - Doc Type: 03-13,
• Copyright Material: NO

the Yampa River in April and May. All fish were implanted with coded wire tags prior to
stocking. No fish were implanted with radio tags.

Obiective 2: Determine the appropriate number and size of bony tail to stock to maximize
survival.

Recaptures

Recapture effort summaries

The total effort expended on the Colorado River was as follows: electrofishing (EL) 99.45 hrs,
seining (SN) 69 habitats, fyke/hoop nets (FN/HN) 131 net nights, and 66 trammel sets (Table 2).
Monitoring on the Colorado River began the fall of 1996 and concluded in the fall of 200 1. The
methods applied and the river miles covered varied widely from year to year, depending on
additional work loads and available personnel.

The total effort expended in the lower Green River was: EL 359.95 hrs, SN 42 habitats, FN/HN 9
net nights, and 9 trammel sets (Table 2). Monitoring in the Green River began in the spring of
1999 and concluded in the summer of 2002. As was the case in the Colorado River, sampling
methods and the area covered varied year to year. Also of note, in 2000, 2001, and 2002 a
portion of the sampling occurred prior to the spring stocking events. This early sampling allowed
for some assessment of bonytail overwintering success. Bonytail collected during pre-stocking
sampling had persisted through at least one winter and potentially more.

Total recaptures

Over the course of all sampling in the Colorado River, 1996-2001, a total of 663 hatchery-reared
bonytail were recaptured, representing 0.8% of all fish released (Table 3). Seventeen (0.02%) of
the fish recaptured in the Colorado River had overwintered and persisted in the system for more
than six months. Most of the long-term recaptures in the Colorado occurred in 2001 (Table 4).
In the Green River, a total of 523 or 0.4% of the stocked bonytail were recaptured between 1999
and 2002. Of the Green River recaptures, 59 fish (0.05%) had overwintered and persisted in the
system for more than 6 months. As in the Colorado River, the majority (31) of the long-term
recaptures in the Green River occurred in 2001 (Table 4).

Other native fish stocking efforts have experienced similar overall recapture rates when stocking
juvenile fish. Age-O Colorado pikeminnow (mean TL 24-55mm) stocked in the San Juan River
showed an overall return rate of 0.3-0.5% and approximately 0.096.10 for fish at large for 6 months
or more (Archer et al. 2000). Overall 0.4-0.8% of juvenile (mean TL < 300 mm) razorback
sucker (Xyrauchen texanus) cohorts stocked in the upper Colorado, Gunnison, and San Juan
rivers were recaptured (Burdick 2002; Ryden 2000). For juvenile razorbacks at large more than 6
months 0.1 % were recaptured in the upper Colorado and Gunnison rivers, and 0.3% were
recaptured in the San Juan River. In contrast, for adult sized razorbacks (mean TL > 300 mm) in

9