Abstract
Laboratory studies of salinity tolerance and avoidance in juvenile paddlefish Polyodon spathula were motivated by concern that stocked individuals of this freshwater species might disperse via coastal marine waders. The tolerance study consisted of replicated 24-h and 96-14 lethal-salinity bioassays with salinity test-levels up to 16 ppt, using juvenile paddlefish acclimated to 0-ppt and 5-ppt salinity water. The avoidance study was comprised of a series of trials in which a vertical salinity gradient tank was used to obtain data on salinity avoidance behavior. Bioassays of high-salinity tolerance indicated 24-h and 96-h lethal limits near 10 and 8 ppt, respectively, whether the fish had been acclimated to freshwater or water with 5-ppt salinity. Salinity avoidance trials suggested that juvenile paddlefish should avoid salinities greater than 4 ppt, again, regardless of salinity acclimation.
Vignali, Carl R (1999). Salinity tolerance and avoidance in juvenile paddlefish, Polyodon spathula. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1999 -THESIS -V5.