Proposed Standard Weight (<i>W</i>_s) Equations and Standard Length Categories for 18 Warmwater Nongame and Riverine Fish Species

Abstract

Relative weight (Wr) is one of several condition indices used to assess the general health of fishes. Standard weight (Ws) equations are required to calculate Wr, but are unavailable for many nongame and riverine fish species. Therefore, we developed Ws equations for the following taxa: longnose gar Lepisosteus osseus, spotted gar L. oculatus, common carp Cyprinus carpio, bigmouth buffalo Ictiobus cyprinellus, river carpsucker Carpiodes carpio, shorthead redhorse Moxostoma macrolepidotum, smallmouth buffalo I. bubalus, white sucker Catostomus commersoni, black bullhead Ameiurus melas, brown bullhead A. nebulosus, flathead catfish Pylodictis olivaris, white catfish A. catus, yellow bullhead A. natalis, white perch Morone americana, yellow bass M. mississippiensis, green sunfish Lepomis cyanellus, rock bass Ambloplites rupestris, and warmouth L. gulosus. These Ws equations were evaluated with statistical validation approaches similar to previously defined regression-line-percentile equations. Standard length categories were developed or revised for 10 of these 18 species (longnose gar, spotted gar, bigmouth buffalo, river carpsucker, shorthead redhorse, smallmouth buffalo, white sucker, brown bullhead, white catfish, and yellow bullhead) to allow for comparison of mean Wr values within and among length categories instead of assessing only population mean Wr .