Use of Strain, Season of Stocking, and Size at Stocking to Improve Fisheries for Rainbow Trout in Reservoirs with Walleyes

Abstract

We evaluated stockings of rainbow trout Oncorhynchus mykiss in Pathfinder and Alcova reservoirs, Wyoming, to determine what combination of strain, season of stocking, and size at stocking maximized angler catch in the presence of walleyes Stizostedion vitreum. Coded wire tags were used to identify individual rainbow trout to stock group. Angler catch of Kamloops rainbow trout and fall rainbow trout in Pathfinder Reservoir exceeded returns of Eagle Lake rainbow trout. Differences in strain performance in Alcova Reservoir were less pronounced. The importance of season of stocking was identified with fall-stocked (August-October) rainbow trout returning to anglers in higher numbers than those stocked during spring (March-June). Size-at-stocking evaluations indicate that large, catchable-size (Ͼ208 mm total length) rainbow trout maximize use of hatchery facilities over stocking greater numbers of small, catchable (178-207 mm) or subcatchable (127-177 mm) sizes. Pond feeding trials conducted with three walleye size-classes and three rainbow trout sizes showed that 127-mm rainbow trout were highly vulnerable to walleyes as small as 330-378 mm. Intermediate-size rainbow trout (178 mm) were not readily consumed by 381-432-mm walleyes, but they were vulnerable to 483-533-mm walleyes. At 229 mm, rainbow trout appeared invulnerable to walleyes in the largest size-class (483-533 mm) we studied. Rainbow trout stocked at large, catchable sizes are probably vulnerable to fewer walleyes compared with small, catchable and subcatchable sizes, allowing greater numbers to survive predation and recruit to the sport fishery.

Largemouth bass consumption demand on hatchery rainbow trout in two Washington lakes

“…For example, it has been suggested that stocking trout in the fall increases survival because warm-and cool-water predators such as largemouth bass and walleye become less active (Wiley et al 1993, Yule et al 2000. However, we observed largemouth bass predation on rainbow trout to occur only during the fall due to spatial habitat overlap and stocking of vulnerable sized fish.…”

An experimental approach to determine esocid prey preference in replicated pond systems

“…Throughout the United States, millions of rainbow trout are stocked annually as sport fish in put-and-take fisheries; however, we have known for more than 50 years that stocked rainbow trout are highly susceptible to predation (Johnson and Hasler 1954), and more recently they have been shown to end up as the primary forage base for piscivores (Marwitz and Hubert 1997, Yule et al 2000, Flinders and Bonar 2008. Additionally, elevated body condition of top predators is correlated with the stocking of rainbow trout (Marwitz andHubert 1997, Flinders andBonar 2008), and exceptional growth rates of top predators have been related to the availability of soft-rayed prey fishes with high energy density and minimal handling time, such as rainbow trout (Beyerle 1971, Johnson andMartinez 2000).…”

Predation by American White Pelicans and Double‐Crested Cormorants on Catchable‐Sized Hatchery Rainbow Trout in Select Idaho Lentic Waters

“…However, angler catch of hatchery trout stocked in lentic environments is affected by numerous factors other than pelican predation, such as rearing conditions in the hatchery (e.g., Davison 1997; Barnes et al 2009), season of stocking and size at release (Yule et al 2000), water quality (Koenig and Meyer 2011), and the presence of piscine and other avian predators (Derby and Lovvorn 1997). Thus a low rate of pelican predation would not necessarily translate directly into high rates of angler catch.…”