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eek 22 rkm 505 Data Logger wing the spawn- :rs in the middle er basin) at river and a large is- congregate an- t the initiation p 1990; Modde s.-Razorback ishing (Smith- i a johnboat). r the spawning )00. Each fish ;ive integrated .e., presence of ) and weighed Fish without a were consulted i PIT tags (i.e., art of an inde- p a genetic re- ::king (i.e., Up- :red Fishes Re- ; and a limited 3 from the river Fish Hatchery .-Radio trans- -azorback suck- a (as per Muell- Z003). We used frequency and ximately 6.5 g ismitter was at- dorsal fin) on 'ore transmitter RAZORBACK SUCKER SPAWNING IN THE GREEN RIVER attachment, each fish was anesthetized with tricane methanesulfonate (MS-222). Anesthetized fish were placed in a square wooden platform (41 x 33 cm), and the gills were irrigated with a dilute solution of MS-222. Two holes were drilled into the keel of each fish using a cordless drill and a 0.23-cm bit. The distance between the holes was approximately 3.5 cm. An absorbable monofila- ment suture (Ethicon 3-0) was fed through a 20- gauge needle until it was exposed on the opposite end. The transmitter, which had four small holes (two anterior and two posterior), was fastened tightly to the keel. Neosporene was applied to the wound following attachment. After attachment, the fish was placed into a live well to recover for approximately 10 min and released near the spawning site. Data-logging stations.-A data-logging station was operated on an island south of the spawning area (Figure 1). The station consisted of three Yagi antennas with four-filaments each. One antenna faced upstream, the second faced downstream, and the third pointed directly at the spawning bar. An- tennas were connected to a Lotek Model SRX 400 logging receiver. A deep-cell battery charged by a photovoltaic panel powered the receiver. The sta- tionary logger recorded data between 1 May and 6 June 2000. The receiver continually scanned for transmitter frequencies and codes. When a radio- tagged fish was detected, the transmitter frequen- cy, code, time, and signal strength were recorded. Signal strength allowed determination of direc- tional movement. From these data, we were able to determine when radio-tagged razorback suckers approached and departed the spawning area, as well as the period each fish spent in the spawning area. For the purposes of separating diurnal and nocturnal use of the spawning site, 0700-1859 hours were considered daylight hours and 1900- 0659 were considered nocturnal hours. Ground survey telemetry.-We determined spe- cific locations of radio-tagged fish on the spawning bar by monitoring their presence during four 24- h periods in May: 16-17, 18-19, 23-24, and 24- 25. Hourly locations of fish with transmitters were determined (by triangulation) over each 24-h pe- riod. A single Lotek radio receiver using a three- element Yagi antenna was used to locate fish from two of five local benchmarks. Fish locations were estimated by triangulating between fixed bench- mark locations. Benchmarks, established with a global positioning system survey, were located on the island adjacent to the spawning area. Bearings were measured using a Suunto compass and su- 939 perimposed onto a map to show the location of radio-tagged fish. Discharge and water tempera- ture for the Green River were obtained from the U.S. Geological Survey stream gauge near Jensen, Utah (09261000). Results Between 1 and 20 May 2000, 18 razorback suck- ers were captured on the spawning site (rkm 504) via electrofishing (Table 1), of which 10 were wild Green River fish and 8 were produced (wild par- ents) and reared at the Ouray NFH and stocked in 1998 and 1999 (1,278 released at ages 6-9; >250 mm TL; Ouray NFH records; Modde et al. 2004). All except two (<400 mm) of these hatchery- reared fish appeared to be in spawning condition (i.e., tuberculated males, females with inflamed genital region). Of the 18 fish collected, transmit- ters were externally attached to 3 wild males and 6 hatchery fish (5 males, lfemale). As part of the species recovery effort (i.e., broodstock for rein- troduction efforts), 6 of the wild fish (1 female, 5 males) were transported to Ouray NFH for devel- opment of a genetic refugium. Among the 9 fish with transmitters, 5 fish were later detected for a minimum of 5 d on the spawning bar. Razorback suckers were present on the bar during the first electrofishing sampling date but occurred in peak numbers on 5 May, after which fewer fish were collected. Because several fish were captured on the first day of electrofishing, it is probable that fish were present in the spawning area before 1 May. Stationary telemetry loggers recorded razorback suckers in the spawning area from 1 to 25 May 2000, which was later than the latest date that fish were taken by electrofishing (Figure 2). Either fish effectively avoided the electrofishing field, or they moved to areas near the spawning site where they were less vulnerable to capture. On 9 May, no fish were collected with electro- fishing, and a single fish was detected with telem- etry equipment in the vicinity of the spawning area. The following day, a telemetry monitoring effort was conducted to locate fish with transmit- ters. Within a range of 5 km upstream and 8 km downstream of the spawning area, only two fish were located (codes 39 and 41). This movement of fish away from the spawning area was coinci- dent with a rapid temperature drop of 2.7°C in a 48-h period (from 14.4°C to 11.7°C). The greatest number of fish detected by telemetry occurred on 11 May when four fish were detected and the av- erage daily temperature was 12.3°C. At least three