Temperature and Scale Size Errors in the Use of [14C]Glycine Uptake by Scales as a Growth Index

Measurement of glycine uptake by largemouth bass (Micropterus salmoides) scales at several acclimation (14, 20, and 26 °C) and incubation (14–32 °C, 3 °C increments) temperatures revealed significant interaction between these factors (P < 0.005). Therefore, comparison of uptake data from several acclimation groups could not be made at any arbitrary "standard" incubation temperature without introducing error. An error-free scale incubation criterion was tentatively proposed as optimum incubation temperature for each fish acclimation temperature, determined from a laboratory response surface model. Incubation temperature of maximum uptake was associated with temperature of maximum body growth of bass which suggests that uptake may be integrated with growth. Use of scale weight to express uptake relative to scale size will probably introduce systematic error, and scale area should provide the "best" measure for normalization of uptake data. Glycine uptake by 14, 20, and 26 °C acclimated scales was linearly related to body growth on a loge–loge basis (P < 0.05); however, within acclimation groups significant correlation was not noted.Key words: acclimation temperature, incubation temperature, response surfaces, largemouth bass, Micropterus salmoides