Effects of Rearing Density on Return to Creel of Hatchery Catchable Rainbow Trout Stocked in Idaho Lentic Waters

Abstract

Evaluating rearing techniques that maximize angler returns to creel of hatchery trout is an essential tool in shaping hatchery management practices and maximizing the public use of hatchery products. The goal of this study was to determine the effects of raceway rearing density on return to creel of catchable‐sized (mean TL ≈ 252 mm) hatchery Rainbow Trout Oncorhynchus mykiss. In 2011 and 2012, Idaho Department of Fish and Game reared catchable‐sized trout targeting three maximum density indices (0.15, 0.25, and 0.30 lb·ft−3·in−1) at three different state fish hatcheries. Each hatchery stocked fish into the same 11 lakes and reservoirs to evaluate return‐to‐creel rates by rearing density. Although there was a trend of lower angler catch for fish reared at a higher raceway density, the relationship was not statistically significant. Instead, angler catch was significantly influenced by fish size at stocking and the surface area of the water being stocked, whereby larger fish and smaller waters had higher return‐to‐creel rates. At the densities tested in this study, we concluded that fish size at stocking is more important than rearing density in determining return‐to‐creel rates for hatchery catchable Rainbow Trout. Rearing trout at a lower density reduces total hatchery production while not providing a sufficient increase in returns to creel to offset the decreased production.

Relative Cost and Post‐Release Performance of Hatchery Catchable Rainbow Trout Grown to Two Target Sizes

“…We found no difference in tag reporting rate between length groups, indicating that the difference in angler catch can be attributed to the angling process itself. Although total catch by anglers was seemingly low in the present study (15.5% for standards, 31.4% for magnums), these results are consistent with other catchable post-release evaluations in Idaho (Meyer and Schill 2014;Cassinelli et al 2016;Cassinelli et al 2018) and other catchable evaluations dating back 80 years (e.g., Shetter and Hazzard 1941;Walters et al 1997). Catchability is of paramount importance for putand-take fisheries, given that the impetus behind such programs is to create immediate fisheries.…”

“…The need for more post-release evaluations of hatchery trout catchable stocking programs was identified over 30 years ago (Hartzler 1988), yet such evaluations remain relatively scarce. One exception to this scarcity is the growing body of literature indicating that larger catchables are more likely to be caught by an angler than smaller catchables (Mullan 1956;Yule et al 2000;Cassinelli et al 2016;Losee and Phillips 2017;Cassinelli and Meyer 2018;Meyer and Cassinelli 2020). However, all of these studies evaluated size of catchables as a secondary objective or tested size-at-release across small geographic and temporal scales.…”

Fisheries Volume 46 Number 8 August 2021

“…We found no difference in tag reporting rate between length groups, indicating that the difference in angler catch can be attributed to the angling process itself. Although total catch by anglers was seemingly low in the present study (15.5% for standards, 31.4% for magnums), these results are consistent with other catchable post-release evaluations in Idaho (Meyer and Schill 2014 ;Cassinelli et al 2016 ;Cassinelli et al 2018 ) Shetter and Hazzard 1941 ;Walters et al 1997 ). Catchability is of paramount importance for putand-take fi sheries, given that the impetus behind such programs is to create immediate fi sheries.…”

“…The need for more post-release evaluations of hatchery trout catchable stocking programs was identifi ed over 30 years ago (Hartzler 1988 ), yet such evaluations remain relatively scarce. One exception to this scarcity is the growing body of literature indicating that larger catchables are more likely to be caught by an angler than smaller catchables (Mullan 1956 ;Yule et al 2000 ;Cassinelli et al 2016 ;Losee and Phillips 2017 ;Cassinelli and Meyer 2018 ;Meyer and Cassinelli 2020 ). However, all of these studies evaluated size of catchables as a secondary objective or tested size-at-release across small geographic and temporal scales.…”

Effects of Baffles on Raceway Cleaning, Fin Erosion, In‐Hatchery Survival, and Postrelease Angler Catch of Catchable‐Sized Hatchery Rainbow Trout

“…However, while catchable stocking programs are popular among anglers, hatchery operation and transport costs associated with catchable rearing and stocking are nevertheless expensive (Hunt et al 2017;Losee and Phillips 2017;Branigan et al 2021). Consequently, numerous hatchery rearing and stocking practices associated with catchable programs have been investigated for decades as a means of maximizing program efficiencies (e.g., Mullan 1956;Larmoyeux and Piper 1973;Elrod et al 1989;Banks and LaMotte 2002;Barnes et al 2009;Cassinelli et al 2016;Cassinelli and Meyer 2018). One such practice is exercising fish during rearing, which has been widely studied (see reviews in Davison 1989Davison , 1997Hammer 1995;and Kieffer 2000).…”