Variation in intrinsic individual growth rate among populations of leatherside chub (Snyderichthys copei Jordan & Gilbert): adaptation to temperature or length of growing season?

Abstract

Variation in intrinsic individual growth rate among populations of leatherside chub (Snyderichthys copei Jordan & Gilbert): adaptation to temperature or length of growing season?Un resumen en españ ol se incluye detrás del texto principal de este artículo.Abstract -Leatherside chub (Snyderichthyes copei Jordan & Gilbert) comprises two lineages (northern and southern) whose centres of geographical range differ by about 3°latitude corresponding to about 30% shorter growing season and about 2°C lower mean temperature during the growing season. We document patterns of variation in sizeat-age among populations of leatherside chub in nature, and we test for variation in intrinsic growth rate of juvenile chub in a commonenvironment experiment to determine if lineages exhibit different intrinsic growth rates. Northern leatherside chubs at ages 1-3 were about 15% shorter in length compared with southern populations. Variation in hatching date or age at maturity could not account for differences in growth and body size, suggesting that temperature-specific intrinsic growth rates differed among populations. Based on a common environment experiment, we found that reaction norms for temperaturespecific growth in length and mass were crossed. At the lower temperature, individuals from the north exhibited higher intrinsic growth in length, and at the higher temperature individuals from the south exhibited higher intrinsic growth in mass. Crossing reaction norms for temperature-specific intrinsic growth rates support a model of local adaptation to thermal regime.

Latitudinal variation in growth among Arctic charr in eastern North America: evidence for countergradient variation?

“…As a result, the ocean temperature gradient along the distributional range that anadromous Arctic charr included in the present analysis (53°-72°N) may experience likely varies by less than about 6°C (Drinkwater & Mountain, 1997). Thus, the broad effect of prevailing maritime currents helps to dampen environmental variation during the important summer feeding growth period with fewer extremes in temperatures occurring in maritime climate zones (Belk et al, 2005). Thus, eastern North American anadromous populations using thermal environments largely influenced by the Labrador Current will generally experience less of a difference in thermal habitat as a function of latitude than will stationary lacustrine populations.…”

Evaluation of temperature-selection differences among juvenile muskellunge originating from different latitudes

“…Local temperature adaptation predicts that the temperatures for optimum growth and energetic processes are adapted to the local temperature conditions and are directly (Levinton 1983;Yamahira and Conover 2002). Alternatively, countergradient variation focuses on differences in the length of the growing season across latitudes and predicts that individuals from cooler environments should select similar or warmer temperatures than conspecifics from warmer environments when presented with a temperature gradient (Conover and Schultz 1995;Freidenburg and Skelly 2004;Belk et al 2005). Selection of warmer temperatures would increase growth rates and, ultimately, result in a large body at the beginning of a long winter (Conover and Present 1990).…”

Genetic variability in reaction norms in fishes

“…4). Intraspecific variability in reaction norms has also provided evidence for countergradient variation in growth in mummichog (Fundulus heteroclitus; Schultz et al 1996), striped bass (Morone saxatilis; Conover et al 1997), tidewater silverside (Menidia peninsulae; Yamahira and Conover 2002), leatherside chub (Snyderichthyes copei; Belk et al 2005), Japanese killifish (Oryzias latipes; Yamahira et al 2007), and Atlantic cod .…”