Shovelnose Sturgeon Spawning in Relation to Varying Discharge Treatments in a Missouri River Tributary

Abstract

Many lotic fish species use natural patterns of variation in discharge and temperature as spawning cues, and these natural patterns are often altered by river regulation. The effects of spring discharge and water temperature variation on the spawning of shovelnose sturgeon Scaphirhynchus platorynchus have not been well documented. From 2006 through 2009, we had the opportunity to study the effects of experimental discharge levels on shovelnose sturgeon spawning in the lower Marias River, a regulated tributary to the Missouri River in Montana. In 2006, shovelnose sturgeon spawned in the Marias River in conjunction with the ascending, peak (134 m 3 /s) and descending portions of the spring hydrograph and water temperatures from 16 C to 19 C. In 2008, shovelnose sturgeon spawned in conjunction with the peak (118 m 3 /s) and descending portions of the spring hydrograph and during a prolonged period of increased discharge (28-39 m 3 /s), coupled with water temperatures from 11 C to 23 C in the lower Marias River. No evidence of shovelnose sturgeon spawning was documented in the lower Marias River in 2007 or 2009 when discharge remained low (14 and 20 m 3 /s) despite water temperatures suitable and optimal (12 CÀ24 C) for shovelnose sturgeon embryo development. A similar relationship between shovelnose sturgeon spawning and discharge was observed in the Teton River. These data suggest that discharge must reach a threshold level (28 m 3 /s) and should be coupled with water temperatures suitable (12 CÀ24 C) or optimal (16 CÀ20 C) for shovelnose sturgeon embryo development to provide a spawning cue for shovelnose sturgeon in the lower Marias River.

Habitat use and population characteristics of potentially spawning shovelnose sturgeonScaphirhynchus platorynchus(Rafinesque, 1820), blue sucker (Cycleptus elongatus(Lesueur, 1817), and associated species in the lower Wisconsin River, USA

“…We found that both species possibly spawn on coarse rocky substrate at depths of 0.8–2.0 m and surface velocities of 0.4–1.0 m/s. Although several previous studies inferred that shovelnose sturgeon spawn on coarse rocky substrate, we could find only one literature citation of a confirmed spawning habitat for shovelnose sturgeon, a natural mid‐channel rocky riffle of unspecified substrate composition, depth, or current velocity in the lower Marias River system, a Missouri River tributary in Montana (Goodman et al., ). However, more literature is available for blue sucker: in the Wabash River in Indiana, spawning blue sucker were captured over substrates of sand, gravel, and cobble at depths of 0.3–3.0 m (Daugherty et al., ).…”

“…In the LWR, timing and duration of presumed shovelnose sturgeon spawning had no obvious relation with river discharge. Conversely, in the Marias River system in Montana, a tributary of the upper Missouri River, spring spawning was associated with rising flows, and spawning did not occur in dry years without a strong spring rise in discharge (Goodman et al., ). However, the Marias River was much smaller, with spring low flows only about 10%–25% of those in the LWR.…”

Spawning related movement of shovelnose sturgeon in the Missouri River above Fort Peck Reservoir, Montana

“…data). The discharge thresholds were based on shovelnose sturgeon spawning in the upper Missouri River that was documented to occur on the descending limb of the hydrograph, coincident to water temperatures within the suitable ranges for spawning and embryonic survival (Goodman, ). In 2008, suitable spawning conditions were from 29 May to 26 July, and in 2009 from 4 June to 22 July.…”

“…Changes in discharge and water temperature associated with the spring pulse are believed to cue spawning migrations in adult sturgeons (Becker, ; Keenlyne and Jenkins, ; DeLonay et al., ). Reproductively active sturgeon can fail to spawn if the environmental cues of discharge and water temperature are absent (Auer, ), and in the Marias River, a tributary to the main stem Missouri River, shovelnose sturgeon have been shown to initiate spawning only when a threshold discharge was reached (Goodman, ). The construction and operation of dams on the Missouri River has altered and decoupled the putative environmental spawning cues of discharge and water temperature thought to initiate spawning in shovelnose sturgeon (Galat et al., ).…”

Spatiotemporal variation in flow-dependent recruitment of long-lived riverine fish: Model development and evaluation

“…Persistent low flow conditions in early spawning season of the drought period forced many gravid females to migrate to and congregate downstream, where flow rates are occasionally high enough during the spawning season for some gravid females to spawn. The role of river discharge in sturgeon spawning may thus serve only as a temporal trigger for the beginning of the spawning season (Goodman et al, 2013;, and other environmental drivers such as water temperature may drive spawning behavior by facilitating physiological processes (e.g., energy allocation) in the final stage of gonad maturation prior to spawning .…”