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It is well known in ecological studies that the choice of spatial scale can influence the possibility of detecting ecological patterns and the type of patterns observed. However, this has rarely been evaluated for fish stock-recruitment (SR) dynamics. Inappropriate scales may result in failure to identify possible SR relationships, especially for species with complicated life history and stock structure and locally generated recruitment. Using American lobster (Homarus americanus) in the Gulf of Maine (GOM) as an example, we tested the hypotheses that the SR relationship is detectable only at certain spatial scales and the functional SR relationships vary with spatial scales. We estimated the SR relationship separately for American lobster in the eastern and western GOM, which have strongly differing oceanographic conditions that may result in different suitable spatial scale and SR dynamics for lobster. We analyzed data of 11 different spatial scales using a Bayesian method. The model fit and performances in the posterior predictive assessment for the SR models were convexly related to the spatial scales. The functional SR relationships differed for different spatial scale. The SR parameter estimates are negatively or concavely related to the spatial scale. The best model was found at medium spatial scale for both the eastern and western GOM, and the scale differed between the eastern and western GOM, suggesting that optimal spatial scale might be process-related. We demonstrated that the choice of spatial scale directly affected the possibility of identifying the SR relationship, the estimation of SR parameters, the type of SR relationships, and the predictive abilities of the SR models. Il est bien etabli dans les etudes ecologiques que le choix de l'echelle spatiale peut influencer la possibilite de detection de motifs ecologiques et le type de motifs observe. Cela n'a toutefois que rarement ete evalue pour la dynamique de recrutement au stock (RS) des poissons. Un mauvais choix d'echelle peut se traduire par l'impossibilite de cerner les relations de RS possibles, en particulier pour les especes caracterisees par un cycle biologique et une structure de stock complexes et un recrutement local. En utilisant l'exemple du homard (Homarus americanus) dans le golfe du Maine (GOM), nous avons verifie les hypotheses voulant que la relation RS ne puisse etre detectee qu'a certaines echelles spatiales et que les relations RS fonctionnelles varient selon l'echelle spatiale. Nous avons estime separement les relations RS pour le homard dans les parties est et ouest du GOM, caracterisees par des conditions oceanographiques tres differentes pouvant se traduire par differentes echelles spatiales convenables et differentes dynamiques de RS pour les homards. Nous avons analyse des donnees de 11 echelles spatiales differentes a l'aide d'une methode bayesienne. Le calage et la performance des modeles dans l'evaluation predictive posterieure pour les modeles de RS presentaient une relation convexe avec les echelles spatiales. Les relations RS fonctionnelles variaient selon l'echelle spatiale. Les estimations des parametres de RS presentent une relation negative ou concave avec l'echelle spatiale. Le meilleur modele etait a une echelle spatiale intermediaire tant pour la partie est que pour la partie ouest du GOM, et l'echelle etait differente pour les deux regions, donnant a penser que l'echelle spatiale optimale pourrait etre liee au processus. Nous avons demontre que le choix de l'echelle spatiale a une incidence directe sur la possibilite d'etablir la relation RS, sur l'estimation des parametres de RS, sur le type de relations RS et sur les capacites predictives des modeles de RS. [Traduit par la Redaction], Introduction Patterns and scales have long been recognized as two of the most important issues in ecological studies (Levin 1992; Schneider 2001). Although often oversimplified, prevalent ways to make data [...]

Most high-resolution, proxy-based paleoclimate research has concentrated on tropical oceans, while mid- and high-latitude marine regions have received less attention, despite their importance in the global climate system. At present, sclerochronological analyses of bivalve mollusks supply the bulk of annual- to subannual-resolution extratropical marine climate data, even though interpretation is complicated by a slowdown of growth with increasing shell age. Hence, in order to address the need for additional high-resolution proxy climate data from extratropical regions, we conducted the first year-long in situ field calibration of the coralline red alga Clathromorphum compactum in the Gulf of Maine, United States. Coralline red algae are widely distributed in coastal regions worldwide, and individual calcified plants can live continuously for several centuries in temperate and subarctic oceans. Stable oxygen isotopes extracted at subannual resolution from growth increments of monitored specimens of C. compactum relate well to in situ-measured sea-surface temperatures during the May to December calcification period, highlighting the suitability of coralline red algae as an extratropical climate archive. Furthermore, there is a strong correlation between a 30 yr [[delta].sup.18]O record of C. compactum and an instrumental sea-surface temperature record (r = -0.58, p = 0.0008) and a proxy reconstruction derived from the bivalve Arctica islandica collected in the central Gulf of Maine (r = 0.54, p = 0.002). Keywords: coralline red algae, paleoclimate, Clathromorphum, Gulf of Maine, sclerochronology.