Proposed Standard Weight (W_s) Equations and Standard Length Categories for Redbreast Sunfish and Spotted Sunfish

Abstract

We developed standard weight (W s ) equations for Redbreast Sunfish Lepomis auritus and Spotted Sunfish L. punctatus using the traditional regression-line-percentile (RLP) technique and the empirical-percentile-linear (EmP-L), and the empirical-percentile quadratic (EmP-Q) method. Individual length and weight data for 175,541 Redbreast Sunfish from 8 to 31 cm TL across 315 populations and 66,851 Spotted Sunfish from 7 to 21 cm TL across 130 populations were used in the final analysis. These fish were collected from 1975 to 2021 by various agency and university personnel from most known populations across the species' native and introduced ranges in North America. We present the EmP-Lderived W s equations for the Redbreast Sunfish as log 10 W = 3.1218 × log 10 L − 5.0018 and the Spotted Sunfish as log 10 W = 3.3343 × log 10 L − 5.3739, where W is weight (g) and L is total length (TL, mm). Equations from all methods exhibited length-related bias, but the EmP-L equations had a median bias of 0-0.6 for the length range that comprised 99.7% (for 8-24 cm TL) of Redbreast Sunfish and 99.0% (for 7-18 cm TL) of Spotted Sunfish in our data set. Regardless of the equation, the most bias was found at the upper end of the length spectrum, so we do not recommend these equations for Redbreast Sunfish ≥30 cm TL or Spotted Sunfish ≥20 cm TL. We also developed standard length categories for Redbreast Sunfish with minimum lengths for five standard length categories of 8, 13, 18, 20, and 25 cm TL for stock, quality, preferred, memorable, and trophy sizes and for Spotted sunfish 5, 10, 13, 15, and 18 cm TL, respectively. Development of a W s equation and standard length categories will aid biologists in assessing condition and size structure of wild Redbreast Sunfish and Spotted Sunfish populations and those being propagated for supplemental stocking into areas with depressed native populations.

Proposed standard weight (Ws) equation and standard length categories for Goldeye

“…The minimum length where weight was determined to be accurate was set where the variance-to-mean ratio did not exceed 0.01 (Neumann and Murphy 1991). All lengths less than the determined minimum length were removed from further analyses along with populations less than 10 individuals (Bonvechio et al 2023). Gerow et al ( 2005) also suggested removing categories with fewer than 50 individuals and making sure length-groups included data from at least three populations.…”

“…All lengths less than the determined minimum length were removed from further analyses along with populations less than 10 individuals (Bonvechio et al. 2023). Gerow et al.…”

“…2021; Bonvechio and Bonvechio 2021; Bonvechio et al. 2023). However, PSD categories have not been developed for Goldeye.…”

“…Proportional size distribution is a convenient index for quantifying length-frequency distributions among populations for various species (Wege and Anderson 1978;Weithman 1978;Gabelhouse 1984). Gabelhouse (1984) used all-tackle world-record lengths listed by the International Game Fish Association to define minimum lengths for five size categories for many sport fish species, but recent studies have proposed accepted values for other species not initially included (Quist et al 1998;Bonvechio et al 2010;Dumont and Neely 2011;Bonvechio et al 2019;Kim et al 2019;Black et al 2021;Bonvechio and Bonvechio 2021;Bonvechio et al 2023). However, PSD categories have not been developed for Goldeye.…”