Xyrauchen texanus

"Habitats required by adults in rivers include deep runs, eddies, backwaters, and flooded off-channel environments in spring; runs and pools often in shallow water associated with submerged sandbars in summer; and low-velocity runs, pools, and eddies in winter. Spring migrations of adult razorback sucker were associated with spawning in historic accounts, and a variety of local and long-distance movements and habitat-use patterns have been documented. Spawning in rivers occurs over bars of cobble, gravel, and sand substrates during spring runoff at widely ranging flows and water temperatures (typically greater than 14 C). Spawning also occurs in reservoirs over rocky shoals and shorelines. Young require nursery environments with quiet, warm, shallow water such as tributary mouths, backwaters, or inundated floodplain habitats in rivers, and coves or shorelines in reservoirs." Source: USFWS (2002).

Flooded lowlands and lower portions of tributary streams presumably served as resting-feeding areas during breeding season in the Green River basin (Tyus and Karp 1990). This fish is often associated with sand, mud, and rock substrate in areas with sparse aquatic vegetation, where temperatures are moderate to warm (Sigler and Miller 1963). It has been collected in flooded gravel pits along the Colorado River, Colorado, and from irrigation canals along lower Colorado River (juveniles, Marsh and Minckley 1989). In the nonbreeding season, adults were most common in shoreline runs and along mid-channel sand bars in the mainstream Green River, with average water depth of less than 2 meters and average velocity of less than 0.5 meters per second (Tyus and Karp 1989). Radio-tagged suckers reintroduced into the Gila River, Arizona, used both sand-bottomed, flat-water, main-channel habitats and quieter pools and eddies adjacent to stronger currents (see Minckley et al. 1991). Hatchery-reared suckers released into the San Juan River inflow of Lake Powell most often used shallowly flooded stands of salt cedar and, in some cases, cobbled shorelines (Karp and Mueller 2002). Limited data indicate that young tend to remain along shorelines, in embayments along sandbars, or in tributary mouths (see Minckley et al. 1991). In Lake Mohave, individuals were associated with inshore habitats except during the hotter months when they moved offshore possibly to avoid warmer water temperatures (Mueller et al. 2000).

Spawning occurs most commonly near shore in streams over silty sand, gravel, or rock substrate at depths of up to about 6 meters (often in water less than 0.6 meters deep); known and suspected spawning sites in the Green and other upper-basin rivers all are in broad, flat-water segments (Minckley et al. 1991). Ripe individuals often have been taken over or near coarse sand, or gravel or cobble bars, in flowing water. In reservoirs, spawning occurs on gravel bars swept clean by wave action; also along shorelines over mixed substrates ranging from silt to cobble (Federal Register, 21 March 1994). Spawning has been observed downstream from major impoundments, below Davis Dam and Hoover Dam (Mueller 1989). Larvae appear to remain in gravel until swim-up (see USFWS 1990); apparently they prefer the shallow littoral zone for a few weeks after hatching, then disperse to deeper waters (see Federal Register, 21 March 1994, p. 13375). Seasonally inundated flood plains provide favorable feeding areas for young.

Recaptures and radio-tracking indicate that individuals may remain in one area (a few km long) for several months (USFWS 1990), but individuals may move 100-200 km or or more over several years (Wick et al. 1982). In Lake Mohave, linear range lengths of 10 adults over 14 months were 18-72 km (mean 39 km) (Mueller et al. 2000).

Usually swims in schools.

Spawning groups can include hundreds of individuals (Mueller et al. 2000). Spawns mainly late Janury-April (rarely to May or June) in the lower Colorado River basin (reservoirs), at temperatures of about 11-21 C (USFWS 1990; Federal Register, 21 March 1994); this is earlier, and the spawning season is longer, than in riverine habitat (Mueller et al. 2000). Spawns when water level rising or peak and water warming. Ripe females have been captured from mid-April to mid-June in northeastern Utah and northwestern Colorado. During spawning 1 female may be attended by 2-12 males. Sexually mature as early as second year (males) or third year (females) under conditions at Dexter NFH, or in fifth or sixth year under other captive regimes (Minckley et al. 1991). Many individuals survive for several decades.