Nous utilisons une technique d’interdatation servant à l’étude des anneaux de croissance des arbres pour produire des données très précises de détermination de l’âge et pour évaluer l’erreur du dénombrement des incréments annuels de croissance (zone de croissance annuelle) chez la panope du Pacifique ( Panopea abrupta), un mollusque à forte longévité, aux îles Tree Nob, nord de la Colombie-Britannique, Canada. To date, crossdating has been used to develop growth chronologies in a variety of marine and freshwater bivalve and fish species, but no study has demonstrated how the technique can be used to dramatically and economically improve accuracy in age data. These inaccuracies obscured major recruitment pulses and underestimated the rarity of strong recruitment events. When compared with crossdated ages, growth increment counts consistently underaged Pacific geoduck, particularly in the oldest individuals. The entire crossdating process was completed using visual techniques, requiring no additional equipment beyond a microscope or microprojector. In this analysis, a total of 432 geoduck individuals were aged using crossdating methods as well as annual growth increment counts. By crossmatching these synchronous growth “bar codes”, all growth increments can be correctly identified and assigned the correct calendar year, including the innermost year of recruitment. Crossdating is the most fundamental procedure of tree-ring analysis and is based on the tendency of environmental variability to synchronize the growth of all individuals at a given site. We apply the tree-ring technique of crossdating to generate highly accurate age data and evaluate error in annual growth increment (annual growth zone) counts for long-lived Pacific geoduck ( Panopea abrupta) in the Tree Nob Islands, northern British Columbia, Canada.
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