Do not cite without author permission SC/61/BRG17 Assessment of BCB bowheads: including estimates of calf production and environmental stochasticity
A stochastic population dynamics model for the BCB bowhead whales which keeps track of the reproductive stage of females is developed. This model is fitted to a variety of data sources, including estimates of total (1+) abundance, the fraction of calves based on aerial surveys, and a potential index...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.565.4853 http://www.iwcoffice.co.uk/_documents/sci_com/SC61docs/SC-61-BRG17.pdf |
| Summary: | A stochastic population dynamics model for the BCB bowhead whales which keeps track of the reproductive stage of females is developed. This model is fitted to a variety of data sources, including estimates of total (1+) abundance, the fraction of calves based on aerial surveys, and a potential index of deviations in birth rates (sea-ice on the eastern Beaufort Sea feeding grounds) using penalized maximum likelihood. The results from the extended assessment are compared with analyses which mimic those on which previous assessments have been based. All model configurations fit the abundance data well. However, only the stochastic models are able to mimic the inter-annual changes in the proportion of calves adequately. Although currently preliminary, this model framework could be extended and used as the basis to evaluate some of the potential impacts of climate change of the dynamics of the BCB bowhead whales, and hence the performance of the Bowhead SLA. |
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