Investigation and implications of spatial and temporal patterns in sex ratio data from West Greenland minke whale catches.

The sub-group based its deliberations on the computations set out below, which were carried out by Givens following input from sub-group members

Prevalence and Abundance of Cyamid “Whale Lice” (Cyamus ceti) on Subsistence Harvested Bowhead Whales (Balaena mysticetus)

We present findings on the prevalence and abundance of cyamid ectoparasites (Cyamus ceti) or “whale lice” on bowhead whales (Balaena mysticetus) harvested for subsistence in the Bering, Chukchi, and Beaufort Seas from 1973 to 2015. Cyamids were present on 20% of the 673 whales that were examined for cyamid ectoparasites. Logistic regression was used to determine factors associated with cyamid prevalence. The probability of cyamid presence increased with age, length, and improving body condition, but decreased over the past 35 years. Cyamid presence was also more probable on whales harvested in the spring than on those harvested in the fall. When present, cyamid abundance was typically low(< 10 per whale). Case histories provide ancillary information about the relationships between abundance of cyamids and their bowhead hosts. Environmental change and increasing anthropogenic disturbances are expected to occur in the Arctic regions inhabited by bowheads. We recommend continued monitoring of subsistence harvested whales for cyamids, as well as further investigations into the roles of environmental and anthropogenic variables in cyamid prevalence and abundance, as part of a comprehensive program of Arctic ecosystem assessment.Nous présentons nos constatations en matière de prévalence et d’abondance de l’ectoparasite cyamidae (Cyamus ceti) ou « pou des baleines » se trouvant sur la baleine boréale (Balaena mysticetus) capturée à des fins de subsistance dans la mer de Béring, la mer des Tchouktches et la mer de Beaufort entre 1973 et 2015. Les cyamidae étaient présents sur 20 % des 673 baleines qui ont été examinées dans le but d’y trouver des ectoparasites cyamidae. La régression logistique a servi à déterminer les facteurs liés à la prévalence de cyamidae. La probabilité de la présence de cyamidae augmentait en fonction de l’âge, de la longueur et de l’amélioration de l’état corporel, mais elle a diminué au cours des 35 dernières années. De plus, la présence de cyamidae était également plus probable chez les baleines capturées au printemps que chez les baleines capturées à l’automne. Lorsque présents, les cyamidae étaient généralement de faible abondance (< 10 par baleine). Les cas types fournissent des renseignements supplémentaires sur les relations entre l’abondance de cyamidae et les baleines hôtes. Des changements environnementaux et de plus grandes perturbations anthropiques sont attendus dans les régions arctiques où évolue la baleine boréale. Nous recommandons la surveillance continue des baleines attrapées à des fins de subsistance pour en détecter les cyamidae. Nous recommandons également des études plus approfondies afin de déterminer le rôle des variables environnementales et anthropiques en matière de prévalence et d’abondance des cyamidae, dans le cadre d’un programme exhaustif d’évaluation de l’écosystème arctique

Population Genetics of Bowhead Whales (Baleana mysticetus) in the Western Arctic

Bowhead whales (Balaena mysticetus) in the Bering, Chukchi, and Beaufort seas experienced a severe reduction as a result of commercial whaling in the 19th century. Since the cessation of commercial whaling, the population has recovered to a size that is approaching pre-whaling estimates. Inupiat and Yupik communities in northern and western Alaska hunt these Western Arctic (WA) bowheads along their migratory path during spring and fall. This hunting is regulated by the International Whaling Commission. Recent but preliminary analysis of available genetic data (207 whales and 10 microsatellite markers) raised the question of the presence of multiple, genetically distinct populations within the WA bowheads. Here we re-examined this question on the basis of a study of 414 whales and 22 newly developed microsatellite loci. We identified widespread departures from Hardy-Weinberg equilibrium; however, we were unable to detect significant evidence of multiple genetic populations within the WA bowheads that could explain this Hardy-Weinberg disequilibrium, particularly when compared to the strength of evidence for differentiation between WA bowheads and other populations from distant regions such as the Okhotsk Sea and eastern Canada. There was conclusive evidence of genetic differentiation among the three regions. The statistical rejection of panmixia within the WA improves our understanding of bowhead whale biology, and the lack of evidence for multiple populations within the WA enables risk-averse management of aboriginal hunting of Western Arctic bowhead whales.La population de baleines boréales (Balaena mysticetus) des mers de Béring, de Tchoukotka et de Beaufort a enregistré un grave déclin en raison de la pêche commerciale à la baleine au XIXe siècle. Depuis que la pêche commerciale à la baleine a cessé, la population de baleines boréales a connu un certain essor au point où elle approche maintenant les estimations de la taille qu’elle avait avant la pêche commerciale à la baleine. Les collectivités Inupiat et Yupik du nord et de l’ouest de l’Alaska chassent les baleines boréales de l’ouest de l’Arctique le long de leur voie de migration au printemps et à l’automne. La chasse est réglementée par l’International Whaling Commission. Des analyses récentes, bien que préliminaires, des données génétiques disponibles (207 baleines et 10 marqueurs microsatellites) ont soulevé la question de la présence de multiples populations génétiquement distinctes au sein de la population de baleines boréales de l’ouest de l’Alaska. Ici, nous avons réexaminé cette question en fonction de l’étude de 414 baleines et de 22 locis microsatellites nouvellement mis au point. Nous avons remarqué d’importantes déviations de l’équilibre de Hardy-Weinberg; toutefois, nous n’avons pas pu trouver de preuve significative de populations génétiques multiples au sein des baleines boréales de l’ouest de l’Alaska qui pourrait expliquer ce déséquilibre de Hardy-Weinberg, plus particulièrement en comparaison avec la force de la preuve de différenciation entre les baleines boréales de l’ouest de l’Arctique et d’autres populations de régions distantes telles que la mer d’Okhotsk et l’est du Canada. Il y avait des preuves concluantes de différenciation génétique entre les trois régions. Le rejet statistique de la panmixie au sein de l’ouest de l’Arctique améliore notre compréhension de la biologie des baleines boréales, et le manque de preuves de populations multiples dans l’ouest de l’Arctique donne lieu à la gestion de l’aversion au risque de la chasse à la baleine boréale de l’ouest de l’Arctique par les Autochtones

Assessment of the Bering-Chukchi-Beaufort Seas Stock of Bowhead Whales with Updated Abundance and Trend Data

In its 1994 assessment of the Bering-Chukchi-Beaufort Seas stock of bowhead whales, the Scientific Committee agreed to use a stock abundance estimate based on data from 1988 because the estimate from the more recent 1993 data was preliminary at that time. Analyses of these recent data have now been revised to produce updated abundance and trend estimates. We present here the results of an assessment like that completed by the SC in 1994, but using these revised abundance and trend estimates. 1 INTRODUCTION The Scientific Committee (SC) of the International Whaling Commission (IWC) used the Bayesian synthesis assessment method (Givens, 1993; Givens et al., 1995a; Raftery et al., 1995a) in its 1994 assessment of the Bering-Chukchi-Beaufort Seas stock of bowhead whales (IWC, 1995). Although a preliminary analysis of data on 1993 stock abundance was available, the SC chose not to include this analysis in their assessment because not all relevant data had yet been included in the analysis..

On Statistical Methods that Permit and Improve the Use of Simpler Model-Based Strike Limit Algorithms

The difference between the dynamics of a population model in an Aboriginal Whaling Management Procedure (AWMP) and the dynamics of either the true stock or the common control program for testing AWMPs is a form of model misspecification. The potential estimation bias introduced by this misspecification provides the opportunity to empirically improve model-based strike limits. We show how to adjust the application of an existing AWMP in order to exploit new data sources or to use old data sources more appropriately. The result can be better strike limits without the need to design ever more complex population dynamics models. For example, age proportion data can be used with the AWMP introduced by Punt and Butterworth (1997) without redesigning their model to be age-stratified. A simple example is presented to isolate the key aspects of the approach. For this example, the proposed approach provides better estimation through more flexible use of all available data, particularly when the ..

Consistency of the local kernel density estimator

The consistency of the local kernel density estimator is proved. This nonparametric estimator is distinguished by its use of scaling matrices which are random and which may vary for each sample point. Its applications include adaptive construction of importance sampling functions.Kernel density estimate Nonparametric Consistency

Comparing Methods for Optimising Strike Limit Algorithms

H-optimisation (Givens, 1997; 1999a; Givens et al. 1999) and U-optimisation (Witting, 1999)---two methods for optimising Strike Limit Algorithms---are compared on theoretical principles and simple examples. Despite some appealing and innovative features, U-optimisation is not a reliable method in its current formulation. Two new H-optimisation strategies are described which incorporate the most appealing aspects of Witting's approach. These new strategies produce results on an example that are virtually identical to those given by U-optimisation, but the new variants would be more reliable in cases where U-optimisation fails. Several calculations suggest, however, that any effort to achieve the goal targeted by U-optimisation and these new strategies may be misguided if strikes are to be continually taken over long time periods. 1 INTRODUCTION Witting (1999) describes an innovative approach for tuning Aboriginal Whaling Management Procedure Strike Limit Algorithms (SLAs), which he den..