Swimming endurance of juvenile pallid sturgeon, Scaphirhynchus albus

Hatchery-reared, juvenile pallid sturgeon (Scaphirhynchus albus) were subje cted to swimming stamina tests in a 100-L Blazka-type swim Funnel at 17-20 C, Endurance was measured at fixed velocities ranging from 10-70 cm/sec, an d sustained, prolonged, and burst swimming speeds were identified for two s ize groups: 17.0-20.5 and 13.0-16.8 cm FL. Maximum observed sustained swimm ing speed (no fatigue after 480 min) was 25 and 10 cm/sec, respectively, fo r the large and small size group. A curvilinear relationship was found betw een endurance and speed over the prolonged/burst speed range. Burst speeds of 55-70 and 40-70 cm/sec were measured for the large and small fish, respe ctively Similar to other lotic, benthic fish, sturgeon could use their pect oral fins and overall body morphology to maintain station against velocity without swimming. Fish typically swam with the ventral body surface in cont act with the tunnel bottom during tests, rarely swimming in the water colum n. Swimming speeds of pallid sturgeon are comparable to speeds reported for similar-sized lake sturgeon (Acipenser fulvescens), but they exhibited low er performance relative to other species. Juvenile pallid sturgeon may inha bit high velocity rivers by taking advantage of low velocity microhabitats.