Data from: Length, body depth, and gape relationships and inference on piscivory among North American centrarchids

Species of Centrarchidae are major components of inland fisheries in much
of North America. Thus, information gained from the assessment of
interspecies interactions and/or quantifying predator-prey relationships
is a useful tool for fisheries managers. Using preserved fish specimens (n
= 717) from 20 species of centrarchids, we made measurements of total
length (TL), standard length (SL), horizontal gape, and body depth for
each individual. We fitted mathematical models that included horizontal
gape and body depth as functions of TL and SL, and TL as a function of SL.
Linear-regression-model fits were generally good (r2 = 0.764-0.998) for
all 20 species, with 61 of 78 possible models having r2 values exceeding
0.90. Horizontal gape–SL (F3,702 = 77.18, P < 0.001) and body
depth-SL (F3,702 = 91.79, P < 0.001) ratios differed significantly
along a gradient that reflected the species' likelihood of piscivory.
Slopes of TL–SL regressions did not vary by species, which enabled
development of a generalized TL–SL model for centrarchids. Supplemental
analyses supported that morphometric measurements had not been influenced
significantly by preservation. Results of this study are useful to
fisheries managers involved with understanding species interactions within
centrarchid-dominated food webs, which are of high priority in most
fisheries-management plans.