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Age-based stock assessments are sometimes rejected by review panels due to large retrospective patterns. When this occurs, data-limited approaches are often used to set catch advice, under the assumption that these simpler methods will not be impacted by the problems causing retrospective patterns in the age-based assessment. This assumption has never been formally evaluated. Closed-loop simulations were conducted where a known source of error caused a retrospective pattern in an agebased assessment. Twelve data-limited methods, an ensemble of a subset of these methods, and a statistical catch-at-age model with retrospective adjustment were all evaluated to examine their ability to prevent overfishing and rebuild overfished stocks. Overall, none of the methods evaluated performed best across the scenarios. A number of methods performed consistently poorly, resulting in frequent and intense overfishing and low stock sizes. The retrospective adjusted statistical catch-at-age assessment performed better than a number of the alternatives explored. Thus, using a data-limited approach to set catch advice will not necessarily result in better performance than relying on the age-based assessment with a retrospective adjustment. Key words: closed-loop simulation, data-limited methods, management advice, retrospective analysis, Introduction In the US, age-based, integrated, fisheries stock assessment models are frequently used to estimate annual stock abundance (biomass), fishing mortality rates, and management reference points (Maunder and Punt 2013). [...]

This study confirms 2 independent accounts of previously undocumented hybridization between Magnolia Warbler (Setophaga magnolia) and American Redstart (S. ruticilla) through morphological and genetic analyses. Hybrids were discovered in 2 locations in eastern North America: Ottawa County, Ohio, USA, and Laval, Quebec, Canada. The hybrids, one male and one female, showed plumage intermediate to both parental species. White eye arcs, yellow wash on the belly, narrow white wing bars, and black lores reflect the Magnolia Warbler parentage, while dark yellow-orange coloration on the sides of the breast and under the wing, yellow on the base of most of the secondaries, and pale yellow patches on the outer tail feathers reflect American Redstart. Sequences of the mitochondrial ND2 gene, the Z-linked muscle-specific kinase (MUSK) gene, and the myoglobin intron-2 (MY02) confirmed maternal ancestry from Magnolia Warblers and paternal ancestry in American Redstarts for both hybrids. There is ample opportunity for this species pair to hybridize; they are congeners with broad range overlap, similar habitat preferences, song structure similarities, and plumage similarities in some age categories. Despite these conditions and the unusually high rate of hybridization within the Parulidae, this hybrid combination has never been documented before, and we suggest that this is a rare event that may be expected anywhere in their broad, overlapping ranges. Received 28 March 2019. Accepted 8 December 2020. Key words: heterospecific, heterozygous, hybridization, Parulidae, Setophaga. Deux cas d'un hybridc de paruline du Nouveau Monde (Setophaga magnolia x S. ruticilla) non documente dans Pest de I'Amerique du Nord Cette etude confirme 2 observations independantes d'hybridation jusqu'ici non documentee entre la Paruline a Tete Cendree (Setophaga magnolia) et la Paruline Flamboyante (S. ruticilla) utilisant les analyses morphologiques et genetiques. Ces hybrides ont ete decouverts a 2 endroits dans Test de I'Amerique du Nord : le comte d'Ottawa, Ohio. Etats-Unis et Laval, Quebec, Canada. Les hybrides, un male et une femelle, avaient un plumage intermediaire aux deux especes parentales. Les sourcils blancs, la tache jaune sur le ventre, les couvertures etroites ct blanches, et les lores noirs rcflctcnt la parente de la Paruline a Tete Cendree, tandis que la coloration jaunc-orangc foncee sur les cotes dc la poitrine et sous l'ailc, jaune a la base de la plupart des remiges secondaires ct des taches jaunes et pales sur les rectrices externes refletent la parente de la Paruline Flamboyante. Les sequences du gene mitochondrial ND2, du gene de la kinase specifique du muscle relie a Z (MUSK), et de rintron-2 de myoglobine (MY02) ont confirme l'ascendance matemellc de la Paruline a Tete Cendree et Fascendance patemelle chez la Paruline Flamboyante pour les deux hybrides. II y a de nombreuses possibilites pour cette paire d'especes de s'hybrider ; ils sont des congeneres qui partagent la plupart dc leurs aires de repartition, des preferences d'habitat similaires, des similitudes de structure de chant, et des similitudes de plumage dans certaines categories d'age. Malgre ces conditions et le taux d'hybridation exceptionnellemcnt eleve chez les Parulidae, cette combinaison hybride n'a jamais ete documentee auparavant. et nous suggerons qu'il est un evenement rare dont on peut s'attendre aux les endroits partages dans leurs aires de repartition respectives. Mot-cles: heterospecifique, heterozygote, hybridation, Parulidae, Setophaga., Hybridization events are of interest to the ornithological community due to their broad implications across topics as disparate as conservation, gene expression, species concepts, taxonomy, and animal behavior (Sibley 1957, [...]

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In high-latitude species with high dispersal ability, such as long-distance migratory birds, populations are often assumed to exhibit little genetic structure due to high gene flow or recent postglacial expansion. We sequenced over 120 low-coverage whole genomes from across the breeding range of a long-distance migratory bird, the Veery (Catharus fuscescens), revealing strong evidence for isolation by distance. Additionally, we found distinct genetic structure between boreal, western montane U.S. and southern Appalachian sampling regions. We suggest that population genetic structure in this highly migratory species is detectable with the high resolution afforded by whole-genomic data because, similar to many migratory birds, the Veery exhibits high breeding-site fidelity, which likely limits gene flow. Resolution of isolation by distance across the breeding range was sufficient to assign likely breeding origins of individuals sampled in this species' poorly understood South American nonbreeding range, demonstrating the potential to assess migratory connectivity in this species using genomic data. As the Veery's breeding range extends across both historically glaciated and unglaciated regions in North America, we also evaluated whether contemporary patterns of structure and genetic diversity are consistent with historical population isolation in glacial refugia. We found that patterns of genetic diversity did not support southern montane regions (southern Appalachians or western U.S. mountains) as glacial refugia. Overall, our findings suggest that isolation by distance yields subtle associations between genetic structure and geography across the breeding range of this highly vagile species even in the absence of obvious historical vicariance or contemporary barriers to dispersal. [ABSTRACT FROM AUTHOR]

The United States Northern Shortfin squid fishery is known for its large fluctuations in catch at annual scales. In the last 5 years, this fishery has experienced increased availability of Illex illecebrosus along the Northeast US continental shelf (NES), resulting in high catch per unit effort (CPUE) and early fishery closures due to quota exceedance. The fishery occurs within the Northwest Atlantic, whose complex dynamics are set up by the interplay between the large‐scale Gulf Stream, mesoscale eddies, Shelfbreak Jet, and shelf‐slope exchange processes. Our ability to understand and quantify this regional variability is requisite for understanding the availability patterns of Illex, which are largely influenced by oceanographic conditions. In an effort to advance our current understanding of the seasonal and interannual variability in this species' relative abundance on the NES, we used generalized additive models to examine the relationships between the physical environment and hotspots of productivity to changes in CPUE of I. illecebrosus in the Southern stock component, which comprises the US fishery. Specifically, we derived oceanographic indicators by pairing high‐resolution remote sensing data and global ocean reanalysis physical data to high‐resolution fishery catch data. We identified a suite of environmental covariates that were strongly related to instances of higher catch rates. In particular, bottom temperature, warm core rings, subsurface features, and frontal dynamics together serve as indicators of habitat condition and primary productivity hotspots, providing great utility for understanding the distribution of Illex with the potential for forecasting seasonal and interannual availability. [ABSTRACT FROM AUTHOR]

We investigated emigration behavior, habitat use, and [Na.sup.+], [K.sup.+]-ATPase activity levels of juvenile steelhead trout (searun rainbow trout; Oncorhynchus mykiss) in Scott Creek, a small coastal watershed with a seasonally closed estuary in central California, USA. Migratory fish moved downstream in the spring with elevated [Na.sup.+],[K.sup.+]-ATPase activity levels. Larger fish (>150 mm) moved downstream during February and March, leaving the stream, whereas fish moving between April and June were typically smaller and tended to recruit to the estuary. The [Na.sup.+],[K.sup.+]-ATPase activity levels of estuarine fish varied during the summer as a function of salinity and temperature, but overall levels declined from peak spring values. Many summer recruits were observed retreating upstream into the watershed when estuarine water quality declined in the fall. Rather than entering the ocean when winter storms reconnected the estuary with the ocean in early winter, many migrated downstream several months later during subsequent springs. The largest smolts observed (>190 mm fork length (LF)) were primarily those that had reared in the estuary the previous summer. Smolts were observed making a single migration from the upper watershed, but they were smaller (~120-190 mm LF) with potentially reduced marine survival. In summary, we observed fish moving between freshwater and estuarine habitats seasonally and adjusting their osmoregulatory physiology as needed. Nous avons etudie le comportement d'emigration, l'utilisation de l'habitat et les niveaux d'activite de la [Na.sup.+], [K.sup.+]-ATPase chez de jeunes truites-arc-en-ciel anadromes (Oncorhynchus mykiss) dans Scott Creek, un petit bassin versant cotier avec un estuaire qui est ferme une partie de l'annee dans le centre de la Californie, E.-U. Les poissons migrateurs se deplacent au printemps avec des niveaux eleves d'activite de la [Na.sup.+],[K.sup.+]-ATPase. Les poissons plus grands (>150 mm) se deplacent vers l'aval en fevrier et mars et quittent le cours d' eau, alors que les poissons qui se deplacent entre avril et juin sont typiquement plus petits et tendent a se rassembler dans l'estuaire. Les niveaux d'activite de la [Na.sup.+],[K.sup.+]-ATPase des poissons dans l'estuaire varient au cours de l'ete en fonction de la salinite et de la temperature, mais diminuent en general a partir des valeurs maximales du printemps. On a observe plusieurs des recrues d' ete retourner en amont dans le bassin versant lorsque la qualite de l'eau de l'estuaire diminue en automne. Au lieu de penetrer dans l'ocean lorsque les tempetes hivernales rattachent a nouveau l'estuaire a l'ocean au debut de l'hiver, de nombreux poissons migrent vers l'aval plusieurs mois plus tard durant les printemps suivants. Les saumoneaux observes les plus gros (>190 mm longueur a la fourche (LF)) sont en majorite ceux qui se sont developpes dans l'estuaire durant l'ete precedent. On observe des saumoneaux faire une migration unique a partir du bassin versant superieur, mais ce sont des poissons plus petits (~120-190 mm LF) dont la survie en mer est potentiellement reduite. En resume, nous avons observe des poissons qui se deplacent aux diverses saisons entre les habitats d' eau douce et de l'estuaire et qui ajustent leur physiologie d'osmoregulation selon leurs besoins. [Traduit par la Redaction], Introduction Pacific salmon (Oncorhynchus spp.) and steelhead trout (Oncorhynchus mykiss, sea-run rainbow trout, hereafter called steelhead) exhibit tremendous life history variation that is typically interpreted as an adaptive response to [...]

ABSTRACT. Migrating birds congregate near the shores of Lake Erie during migration and may be funneled through small green spaces within the urban matrix of Great Lake coastal cities, where [...]

THE WORLD'S RAREST BIRDS. By Erik Hirschfeld, Andy Swash, and Robert Sill. Princeton University Press, Princeton, New Jersey, USA. 2013. 360 pages. ISBN: 9780691155968. $45.00 (hardcover); RARE BIRDS OF NORTH [...]