Using Radiotelemetry to Evaluate Poststocking Survival and Behavior of Large Fingerling Walleye in Three Iowa, USA, Lakes

Stocking Walleye Sander vitreus is a common management tool to augment populations where natural reproduction is limited. Some hatcheries have progressively raised larger fingerling Walleye to improve poststocking survival; however, little is known about the poststocking survival and behavior of large fingerling Walleye. We sought to evaluate the poststocking daily apparent survival, depth use, dispersal, and home range size of large fingerling Walleye (>200 mm TL) in three Iowa, USA, lakes. Walleye (209-265 mm; n = 15 per lake [45 fish total]) were implanted with radio tags, stocked on October 26-30, 2017, and tracked until May 30, 2018. Cormack-Jolly-Seber recapture models estimated that Walleye apparent survival increased with days poststocking and fish length, resulting in 76% (95% CI = 44-89%) cumulative survival by May. Walleye in Brushy Creek Lake were located in deeper water (mean +/- SE = 5.1 +/- 0.2 m) than those in Big Creek Lake (3.3 +/- 0.2 m) or East Okoboji Lake (1.7 +/- 0.1 m), but depth use did not vary with days poststocking. Walleye dispersed an average of 1,355 +/- 234 m within 13 d across all lakes, with home range size being larger in Big Creek Lake (mean +/- SE = 67.9 +/- 21.7 ha) than in Brushy Creek Lake (15.5 +/- 15.7 ha) or East Okoboji Lake (31.0 +/- 14.0 ha). Our results indicate that Walleye poststocking survival is high overall, with most mortality occurring within 20 d as Walleye are dispersing, suggesting that managers should focus on improving survival during this critical period to improve stocking success.