Upstream swimming performance of adult white sturgeon: Effects of partial baffles and a ramp
baffles, barriers, behavior, bypass, California, dams, estuary, fish ladder, flume, high velocity, sturgeon, swimming, swimming ability, swimming performance, tail-beat frequency, upstream, upstream passage, vertical slot
Journal or Book Title
Transactions of the American Fisheries Society
The upstream passage of sturgeon (family Acipenseridae) past barriers such as dams has become a concern of fisheries managers in California. Knowledge about the swimming abilities of adult sturgeon species, particularly with relationship to fish ladders, is limited. Wild adult white sturgeon Acipenser transmontanus (n = 25; total length, 135-198 cm) captured in the San Francisco Estuary and Yolo Bypass toe drain were swum in a variable-speed aluminum flume (24.4 m long x 2.1 m wide x 1.4 m deep) to evaluate swimming behavior around simulated fish-ladder-type partial baffles. Four baffle types (one horizontal ramp and three different vertical slot designs) set in two configurations were tested at three velocity regimes (velocity range around baffles, 0.28-2.52 m/s). In general, faster velocities (0.76-1.07 m/s) cued fish to swim upstream sooner (<= 100 s). Among the baffle types, the percentage of successful passage was variable, and no statistically significant pattern was detected. The tail-beat frequency of fish significantly increased in the high-velocity (to 2.52 m/s) regions of the flume adjacent to the energy-dissipating baffles, where sturgeon were able to pass by swimming in bursts, followed by a resting and recovery period in slower water. Successful white sturgeon passage structures should incorporate rapid-velocity (e.g., 0.84-2.52-m/s) sections between somewhat slower (e.g., 0.5-14.68-m/s) sections for rest and recovery.