Search

To identify processes potentially contributing to the differential marine survival rates of Chinook salmon Oncorhynchus tshawytscha and coho salmon O. kisutch originating from Southeast Alaska, we compared the early marine ecology of the two species during the critical first summer in marine waters. We predicted that the higher survival rates for coho salmon relative to Chinook salmon were related to the larger size, faster growth, or different habitat or species associations of coho salmon. Our size and growth expectations were largely substantiated: juvenile coho salmon were larger than juvenile Chinook salmon and had faster length-based growth, although weight-based growth rates were similar. The most obvious difference was in their distributions. Juvenile coho salmon overlapped spatially and temporally with abundant juvenile pink salmon O. gorbuscha and chum salmon O. keta, whereas juvenile Chinook salmon were geographically separated from other salmonids. This suggests that coho salmon benef...

We report stock composition estimates for immature (ocean-age .1 and .2) sockeye salmon Oncorhynchus nerka distributed across the Bering Sea in late summer and fall. We establish a baseline data set composed of single-nucleotide polymorphism markers that can achieve very high accuracies in identifying sockeye salmon stocks from throughout their range in Asia and North America. We demonstrate the capabilities of this data set to address high-seas salmon issues by analyzing samples collected by researchers from Russia, Japan, and the United States during late summer and fall 2002–2004 as part of the Bering–Aleutian Salmon International Survey. According to our findings, (1) Gulf of Alaska (GOA) stocks formed a significant portion of the immature sockeye salmon migrating in the eastern and central Bering Sea in summer and fall, and western GOA stocks had a broader distribution in the Bering Sea than eastern GOA stocks; (2) Asian stocks migrated as far east as the western Aleutian Islands and the Don...

This study continues the identification monitoring of local sockeye salmon stocks in the Exclusive Economic Zone of Russia on the basis of scale criteria. This study was launched in 2002 as a part of BASIS (the Bering-Aleutian Salmon International Survey). Scale samples of immature sockeye salmon from the trawl catches of the R/V TINRO in the western Bering Sea in August–October 2006 were used for the analysis. The total number of these mixed samples was 1681 specimens for age definition and 1290 specimens for stock identification. The baseline samples (scales from 3162 specimens from Kamchatka, Chukotka and Alaska) were collected by the Kamchatka Research Institute of Fishery and Oceanography (KamchatNIRO), Chuckchee Branch of TINRO (ChukotTINRO), North-East Fishery Protection Service (Sevvostrybvod) and the Alaska Dept. of Fish and Game in the summer of 2006. The results of the analysis indicate the dominant role of the Bristol Bay complex of stocks in the formation of sockeye salmon stocks in the western Bering Sea for the period of the survey: their share was estimated as 55.3% or 88.18 million individuals The most frequent among the Asian stocks were the fishes from the Kamchatka (15.0% or 23.85 million individuals) and Ozernaya Rivers (14.5% or 23.07 million individuals). The summary contribution of minor stocks from north-eastern Kamchatka and Chukotka was also high (11.7% or 18.64 million individuals). The contribution of West Kamchatkan minor stocks was low (3.5% or 5.61 million individuals).

On a determine de facon subjective l'âge des poissons en eau douce afin d'appliquer les techniques d'analyse de la disposition des ecailles, ce qui permettait de distinguer les truites arc-en-ciel d'elevage et sauvages (Onchorhynchus mykiss) dans des groupes melanges en haute mer. A cette fin, nous avons utilise les mesures des ecailles de truites arc-en-ciel adultes d'elevage et sauvages qui revenaient dans le Columbia en 1991 et en 1992 pour elaborer une technique quantitative independante de determination de l'âge et evaluer sa performance. Les meilleurs resultats ont ete obtenus avec un estimateur du maximum de vraisemblance direct a six variables (estimations ponctuelles s'etablissant en moyenne a 94% dans les echantillons pour essai ne renfermant que des poissons d'elevage ou des poissons sauvages). Les erreurs des estimations variaient selon la composition et la taille de l'echantillon mixte. L'estimateur du maximum de vraisemblance (utilisant les donnees de base mises en commun de 1991 et 1992 pour le Columbia) a identifie correctement un echantillon de truites arc-en-ciel sauvages retournant au Kamchatka (Russie), en 1994, et il etait legerement biaise (sous-estimation de 5% de la proportion de poissons d'elevage) lors de l'identification d'un echantillon mixte du golfe de l'Alaska en 1995. L'inclusion d'autres donnees de base pour tenir compte d'une plage plus vaste de variation des profils de croissance des ecailles des populations du Pacifique Nord peut reduire davantage le biais des estimations du golfe de l'Alaska. Nous sommes d'avis que cette technique presente un bon potentiel pour estimer les proportions de truite arc-en-ciel d'elevage et de truites arc-en-ciel sauvages dans des groupes melanges en haute mer.

A new experimental method for the evaluation of myocardial constitutive models combines magnetic resonance (MR) radiofrequency (RF) tissue-tagging techniques with iterative two-dimensional (2-D) nonlinear finite element (FE) analysis. For demonstration, a nonlinear isotropic constitutive model for passive diastolic expansion in the in vivo canine heart is evaluated. A 2-D early diastolic FE mesh was constructed with loading parameters for the ventricular chambers taken from mean early diastolic-to-late diastolic pressure changes measured during MR imaging. FE solution was performed for regional, intramyocardial ventricular wall strains using small-strain, small-displacement theory. Corresponding regional ventricular wall strains were computed independently using MR images that incorporated RF tissue tagging. Two unknown parameters were determined for an exponential strain energy function that maximized agreement between observed (from MR) and predicted (from FE analysis) regional wall strains. Extension of this methodology will provide a framework in which to evaluate the quality of myocardial constitutive models of arbitrary complexity on a regional basis.