Suitability of Lake Sturgeon growth rings in chronology development

The purpose of this investigation was to determine if ring widths in the cr oss section of lake sturgeon pectoral fin rays satisfy three criteria requi red of structures used in the development of growth chronologies. First, ri ng widths must be related to the overall somatic growth of the organism. Se cond, ring widths must demonstrate synchrony of interannual growth variatio n among individuals within a population. Finally, fin ray rings and growth chronologies should be related to both interpopulation and interannual vari ations of known environmental factors. This research indicated that ring wi dths document variations in somatic growth. Average fin ray cross-sectional radii at age 25 were related to total length using data from seven populat ions sampled across North America. This investigation also suggested that g rowth ring widths were influenced by large-scale, population-wide, extrinsi c factors in two ways. First, differences between populations in fin ray cr oss-sectional radii at age 25 were strongly correlated with mean annual, su mmer, and winter air temperatures. Second, growth chronologies developed fr om populations that demonstrate significant synchrony of interannual growth variations among members are consistently positively correlated to past ai r-temperature records. This research has provided evidence that growth ring s contained in the cross section of the lake sturgeon pectoral fin ray can be used in the construction of growth chronologies.