Spawning and Movements of Razorback Sucker, Xyrauchen texanus, in the Green River Basin of Colorado and Utah

Razorback sucker transbasin movement through Lake Powell, Utah

“…The razorback sucker is a robust, river catostomid with maximum size of about 1 m total length (TL) and 5-6 kg (Minckley 1973), although adults are typically 400-700 mm TL and weigh less than 3 kg (McCarthy and Minckley 1987). Females appear to reach larger sizes than males and have relatively smaller fins (Minckley 1983;Tyus and Karp 1990;, whereas males develop stronger, more dense nuptial tubercles on surfaces of the anal and caudal fins, caudal peduncle, and postero-lateral body . Adults are elongated and slightly compressed laterally, with a bony, sharp-edged dorsal keel immediately posterior to the occiput.…”

“…Tag-recapture and telemetry data indicate that razorback sucker in the middle Green River constitute a single reproducing population (Modde and Irving 1998). Known spawning sites are located in the lower Yampa River and in the Green River near Escalante Ranch between river km 492 and 501 (distance upstream from Colorado River confluence), but other, less-used sites are probable (Tyus and Karp 1990;Modde and Irving 1998). Lanigan and Tyus (1989) estimated a middle Green River population of 948 adults (95% confidence interval: 758-1,138).…”

“…A major cause of decline has been loss of a contiguous complement of habitats used by the various life history phases. Adult razorback sucker can migrate considerable distances to and from spawning sites (Tyus and Karp 1990 Ten barriers are identified in the upper basin upstream of Glen Canyon Dam within occupied habitat of razorback sucker (Burdick and Kaeding 1990;; Table 3). Five of these barriers are classified as medium or high-head structures that are partial or seasonal barriers to fish movement or that have been modified to allow passage.…”

“…In rivers, they usually are captured in lower velocity currents, more rarely in turbulent canyon reaches (Tyus 1987;Lanigan and Tyus 1989;Tyus and Karp 1990;). An exception may be in the San Juan River, where hatchery-reared, radio-tagged adults preferred swifter mid-channel currents during summer-autumn base-flow periods (Ryden 2000).…”

Environmental assessment of remedial action at the Slick Rock uranium mill tailings sites, Slick Rock, Colorado

“…Tyus (1987) and McAda and Wydoski (1980) reported springtime aggregations of razorback suckers i n off-channel impoundments and tributaries t h a t were bel ieved t o be associated w i t h reproductive activities. Tyus and Karp (1990) and Osmundson and Kaeding (1991) reported off-channel habitats t o be much warmer t h a n t h e main stem river and that razorback suckers presumably moved t o these areas f o r feeding, resting, sexual maturation, spawning, and other a c t i v i t i e s associated w i t h t h e i r reproductive cycle. While razorback suckers have never been directly observed spawning i n t u r b i d riverine environments w i t h i n the Habitat requirements of young and juvenile razorback suckers i n the wild are largely unknown, particularly i n native riverine environments.…”