Publications by authors named "J M Straley"
Given recent declines in North Pacific humpback whale (Megaptera novaeangliae) reproductive output and calf survival, there is additional urgency to better understand how mother-calf pairs allocate energy resources across their migratory cycle. Here, unoccupied aerial system (UAS; or drone) photogrammetry was used to quantify the body size and condition (BC) of humpback whales on their Hawai'i (HI) breeding and Southeast Alaska (SEAK) feeding grounds. Between 2018 and 2022, we collected 2410 measurements of 1659 individuals.
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- Isolation by distance and geographic boundaries have shaped the population genetic structure of harbour porpoises along the Pacific coast, with a focus on Alaska where recent research used both tissue and environmental DNA (eDNA) samples to fill gaps in previous studies.* -
- The study found limited genetic differentiation among harbour porpoise populations based on nuclear SNP data, but mtDNA analysis revealed significant structuring, especially between the Gulf of Alaska and the eastern Bering Sea, suggesting restricted gene flow and potential natal site fidelity.* -
- The targeted eDNA sampling in Southeast Alaska significantly enhanced the genetic dataset, indicating a population boundary within the recognized Southeast Alaska Stock, which is vital for informing conservation efforts and mitigating fisheries conflicts.*
In two dimensions, the average electrical conductance from a point in a percolating network to the network boundary can be related by a conformal transformation to the conductance from one point to another in an unbounded network. We verify that this works at the percolation threshold for the square.
View Article and Find Full Text PDFFor the 40 years after the end of commercial whaling in 1976, humpback whale populations in the North Pacific Ocean exhibited a prolonged period of recovery. Using mark-recapture methods on the largest individual photo-identification dataset ever assembled for a cetacean, we estimated annual ocean-basin-wide abundance for the species from 2002 through 2021. Trends in annual estimates describe strong post-whaling era population recovery from 16 875 (± 5955) in 2002 to a peak abundance estimate of 33 488 (± 4455) in 2012.
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- * The dataset covers 13 regions and includes data on 27,956 unique humpback whales from 2001-2021, with an impressive identification accuracy of 97-99% using advanced machine learning.
- * This resource aims to facilitate collaborative research on humpback whales and their habitats, especially as the ocean undergoes significant ecological changes.