We used annual increments in the pectoral fin rays of lake sturgeon (Acipenser fulvescens) to assess growth synchrony. We based our decision criteria on correlation among individual chronologies developed from samples collected in the Saskatchewan River, Saskatchewan, and Lake St. Clair and the Mattagami River, Ontario. Initially, correlations among chronologies were not significant within these three populations. However, as mean ageing error was reduced, correlations among chronologies increased to significant levels in samples from the Saskatchewan River and Lake St. Clair. Correlations were not significant among consistently aged fish sampled from the Mattagami River. We conclude that interannual growth variation in lake sturgeon is influenced by population-wide extrinsic factors in some populations. Our results suggest that both growth synchrony and ageing error should be quantified during the construction of growth chronologies for all organisms.

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Interannual growth variations were compared among neighbouring populations of lake sturgeon (Acipenser fulvescens) and white spruce (Picea glauca), white pine (Pinus strobus), and red pine (Pinus resinosa). Measures of growth were obtained by removing long-term trends from widths of rings in the hard tissues of both aquatic and terrestrial organisms and assembling these measures into growth chronologies. Interannual growth variations were negatively correlated (r) between sturgeon and nearby tree population chronologies for those fish populations that displayed strong interseries correlation (r ). The three sturgeon population chronologies developed from individuals that displayed the lowest interseries correlation coefficients failed to display significant correlation with tree growth. The results of this investigation indicate that the negative relationships between fish and tree growth may be related to annual fluctuations in air temperature. In general, fish population chronologies displayed positive correlation with measures of air temperature during the current season of growth, while tree population chronologies displayed negative correlation with air temperatures from either the current or the previous season of growth.Résumé : Nous avons comparé les variations interannuelles de la croissance entre des populations voisines d'esturgeon jaune (Acipenser fulvescens) et d'épinette blanche (Picea glauca), de pin blanc (Pinus strobus) et de pin rouge (Pinus resinosa). Nous avons obtenu les mesures de la croissance en éliminant les tendances à long terme de la largeur des anneaux dans les tissus durs des organismes tant terrestres qu'aquatiques, et en assemblant ces mesures en chronologies de croissance. Les variations interannuelles de la croissance étaient négativement corrélées (r) entre les chronologies de l'esturgeon et des populations d'arbres voisines pour les populations de poissons qui présentaient une forte corrélation interséries (r ). Les trois chronologies de populations de poissons construites à partir des individus qui présentaient les plus bas coefficients de corrélation interséries n'ont pas présenté de corrélation significative avec la croissance des arbres. Les résultats de notre étude indiquent que les relations négatives entre la croissance des poissons et celle des arbres peuvent être liées à des fluctuations annuelles de la température de l'air. En général, les chronologies des populations de poissons présentaient une corrélation positive avec les mesures de la température de l'air pendant la saison de croissance en cours, alors que les chronologies des populations d'arbres montraient une corrélation négative avec les températures de l'air tant pendant la saison en cours que pendant la saison précédente de croissance.[Traduit par la Rédaction] 2356LeBreton and Beamish

The purpose of this investigation was to determine if ring widths in the cross section of lake sturgeon pectoral fin rays satisfy three criteria required of structures used in the development of growth chronologies. First, ring widths must be related to the overall somatic growth of the organism. Second, ring widths must demonstrate synchrony of interannual growth variation among individuals within a population. Finally, fin ray rings and growth chronologies should be related to both interpopulation and interannual variations of known environmental factors. This research indicated that ring widths document variations in somatic growth. Average fin ray cross‐sectional radii at age 25 were related to total length using data from seven populations sampled across North America. This investigation also suggested that growth ring widths were influenced by large‐scale, population‐wide, extrinsic factors in two ways. First, differences between populations in fin ray cross‐sectional radii at age 25 were strongly correlated with mean annual, summer, and winter air temperatures. Second, growth chronologies developed from populations that demonstrate significant synchrony of interannual growth variations among members are consistently positively correlated to past air‐temperature records. This research has provided evidence that growth rings contained in the cross section of the lake sturgeon pectoral fin ray can be used in the construction of growth chronologies.