Latitudinal Influence on First-Year Growth and Survival of Largemouth Bass

Abstract

We examined the effects of latitude of origin on the first-year growth and survival of largemouth bass Micropterus salmoides. We brought largemouth bass from three latitudinally disparate populations (northern largemouth bass M. s. salmoides from south-central Wisconsin; Florida largemouth bass M. s. floridanus, originally from central Florida but currently stocked throughout Alabama; and native northern largemouth bass from southern Alabama) to a common rearing environment to compare their age-0 growth over two replicate growing seasons. During 1999, the northern subspecies from Wisconsin grew faster than the northern or Florida subspecies from Alabama. However, in 2000 the Florida subspecies grew faster than the age-0 fish from either northern subspecies population. Our results indicate that the effects of prey availability and age-0 density can overwhelm any predisposition for growth based on latitudinal or genetic origin. Given concerns about the genetic consequences of largemouth bass stockings, the lack of any consistent growth advantage in the first year represents an important piece of information to be taken into account when deciding about stocking nonnative subspecies of largemouth bass.