Using tree-ring crossdating techniques to validate annual growth increments in long-lived fishes

Abstract

We applied crossdating, a dendrochronology (tree-ring analysis) age validation technique, to growth increment widths of 50 Sebastes diploproa otoliths ranging from 30 to 84 years in age. Synchronous growth patterns were matched by the following: (i) checking the dates of conspicuously narrow growth increments for agreement among samples and (ii) statistically verifying that growth patterns correlated among samples. To statistically verify pattern matching, we fit each time series of otolith measurements with a spline, and all measurements were divided by the values predicted by the curve. This standardized each time series to a mean of 1, removing the effects of age on growth and homogenizing variance. Each time series was then correlated with the average growth patterns of all other series, yielding an average correlation coefficient (r) of 0.53. Average growth of all 50 samples was significantly correlated with an upwelling index (r = 0.40, p = 0.002), the Pacific Decadal Oscillation (r = -0.29, p = 0.007), and the Northern Oscillation Index (r = 0.51, p = 0.0001), corroborating accuracy. We believe this approach to age validation will be applicable to a wide range of long-lived marine and freshwater species.Résumé : Nous avons utilisé la datation croisée, une technique de validation de l'âge en dendrochronologie (analyse des anneaux des arbres), pour étudier les largeurs des incréments de croissance des otolithes de 50 Sebastes diploproa, âgés de 30 à 84 ans. Les patrons de croissance synchronisée ont été corroborés (i) en nous assurant que les dates d'incréments particulièrement étroits correspondent dans les échantillons et (ii) en vérifiant statistiquement que les patrons de croissance sont en corrélation dans les différents échantillons. Pour vérifier statistiquement la correspondance des patrons, chaque série chronologique de mesures d'otolithes est ajustée à une spline et toutes les mesures sont divisées par les valeurs prédites par la courbe. Cette opération standardise chaque série chronologique autour d'une moyenne de 1, éliminant les effets de l'âge sur la croissance et rendant la variance homogène. Chaque série chronologique est alors mise en corrélation avec le patron de croissance moyen des autres séries, ce qui génère un coefficient de corrélation (r) moyen de 0,53. La croissance moyenne de l'ensemble des 50 échantillons est en corrélation significative avec l'indice d'affleurement (upwelling) (r = 0,40, p = 0,002), l'oscillation décennale du Pacifique (r = -0,29, p = 0,007) et l'indice d'oscillation boréale (r = 0,51, p = 0,0001), ce qui confirme sa précision. Nous croyons que cette méthode de validation de l'âge pourra s'appliquer à une variété d'espèces de mer et d'eau douce à grande longévité.[Traduit par la Rédaction] Black et al. 2284

Growth variability in the splitnose rockfish Sebastes diploproa of the northeast Pacific Ocean: pattern revisited

“…Dorn (1992) also suggested that since euphausiids are the principal prey not only for splitnose rockfish and other Sebastes species, but also support numerous fish populations of the California Current System, it is unlikely that changes in the abundance of several Sebastes species alone could have had a substantial impact on the overall abundance of euphausiids. Environmental effects on splitnose rockfish growth were studied further by Black et al (2005) and Black (2009) using crossdating technique from dendrochronology. Crossdating is based on the assumptions that growth increment width in hard parts, like otoliths, is limited by some aspect of climate, and since the intensity of this climatic variable fluctuates over regular time intervals, climate induces covarying growth patterns in otolith increment widths much as it does in tree rings (Black et al 2005).…”

“…Environmental effects on splitnose rockfish growth were studied further by Black et al (2005) and Black (2009) using crossdating technique from dendrochronology. Crossdating is based on the assumptions that growth increment width in hard parts, like otoliths, is limited by some aspect of climate, and since the intensity of this climatic variable fluctuates over regular time intervals, climate induces covarying growth patterns in otolith increment widths much as it does in tree rings (Black et al 2005). Black et al (2005) studied annual growth increments formed in splitnose rockfish otoliths collected between Point Conception and Cape Mendocino (Fig.…”

Influence of Basin‐ and Local‐Scale Environmental Conditions on Nearshore Production in the Northeast Pacific Ocean

“…Fish were collected by using a combination of hook-and-line sampling, trammel-netting, and spearfishing in shallow (<15 m) rocky reef habitats from 2009 to 2011. Otoliths were removed, sectioned, and mounted on slides to measure annual increment widths on high-resolution digital images that were captured with a digital camera (Leica DFC Model 425 or 450; 5-megapixel resolution) mounted on a stereomicroscope (Leica Model MZ6 or M60) under 20-40× magnification following the methods of Black et al (2005). These polishing and photographing procedures were sufficient to clearly reveal growth increment structure in most of the samples; only otoliths with clearly defined growth increment boundaries were used in the study.…”

“…These polishing and photographing procedures were sufficient to clearly reveal growth increment structure in most of the samples; only otoliths with clearly defined growth increment boundaries were used in the study. Dendrochronology crossdating procedures were used to verify that all increments were assigned the correct calendar year of formation (Black et al 2005) and to assess measurement error. If measurement error was high, visual crossdating and the statistical interseries correlation results from the software COFECHA (Grissino-Mayer 2001) were used to determine whether there was low synchrony among individuals, indicative of high error rates or weak environmental signals.…”

Age determination in common carp Cyprinus carpio: history, relative utility of ageing structures, precision and accuracy

“…Black et al 2005;Tracey et al 2016). With regard to longevity, estimated ages of 35 (Bajer and Sorensen 2010) and 23 years (Brown et al 2003) have been reported for carp based on otolith sections, although the oldest (mark-recapture validated) age using this method has been up to 14 years ).…”