WSP09772 - Laserfiche WebLink

Home Browse Search

Table 2. Summary of sampling for stocked bonytails conducted on the Colorado River, 1998. SAMP OCASS refers to sampling occasions, EFF = effort. Species codes are as follows; CS - squawfish, CH - chubs (roundtails unless - indetenninatejuveniles), BT - bonytail, BH - bluehead suckers, FM - flannelmouth suckers, CC - channel catfish, CP - carp, BB - black bullhead, GS - green sunfish, WS - white sucker. GEAR DATES Ri'b SAMP NET EFF CS CH BT BH FM cc CP BB GS W OCASS SETS (hrs) S FYKE 980325, IOB- 16 72 \825 1 11 ]9 4 1\ 207 5 57 9 I 980813 64.9 TRAM 980810 . 98.6 - 4 66 132 7 8 9 1\ 2 13 73.4 ELEC 980429 - 98.5. 2 NA 5.2 5 7 ]} 60.. 117 35 62 I FISH 980617 89.0 TOT 6 31 50 .72 137 253 61 . 57 9 2 Of the fifty bonytails recaptured this past field season: one was from the October, 1997 stocking (the fish had grown 5 mrn and moved 2 miles upstream during it's 255 days in the river), three were the larger sized fish (N=114) stocked March 18, 1998 (one of which was a tuberculated, ripe male collected on April 29, 1998 and one was a radio implanted fish), the remainder were the. small sized fish stocked on April 20 , 1998. In addition, the FWS out of Grand Junction, CO collected one of the large sized bonytails on May 28, 1998 at Colorado River mile 63.9, which constitutes the greatest movement of a recaptured fish. The overwhelming majority (95.4%) of recaptures were found in a 4 mile stretch of river immediately downstream of the release site. However, two fish were recaptured on June 30, 1998 upstream of tile release site at river miles 96.3 and 99.4. Individual bonytail growth at the time of recapture varied between -2 nun and 31 mrn; growth rates will be determined at a later date. Obiective 3 - Radio Telemetry Similar to the efforts in the fall of 1997, ten bonytails (1996 cohort; Table 3) were implanted with radio transmitters at the Wahweap facility on March 9 , 1998. Following implantation of the external antenna modules (ATS Model 10-18; 80- day transmitter life expectancy) the fish were retumedto the pond for a week-long period of recuperation. The fish were stocked at RM 94.3 on March 18, 1998. All tracking was done from the ground. We tracked on 36 occasions between March 18, 1998 and August 5,1998 (140 days post-implant). We covered the Colorado River from &\1110 to the confluence. Many of the fish initially moved upstream of the release site and remained there for approximately one month. The furthest upstream contact was at RM 101.8 miles where a bonytail was tracked through the night of August 5-6, 1998. Our crews tracked fish as far downstream as RM 79, however NPS crews tracking razorback sucker in the lower Colorado may have contacted one of the bonytails as far do\\nstream as RM 18.6. 25-4