Eastern North Pacific gray whale calf production 1994-2023

Details

• Personal Author:
  Eguchi, Tomoharu ; Lang, Aimée R. ; Weller, David W.
• Corporate Authors:
  United States. National Marine Fisheries Service ; Southwest Fisheries Science Center (U.S.)
• NOAA Program & Office:
  NMFS (National Marine Fisheries Service) ; SWFSC (Southwest Fisheries Science Center)
• Description:
  Eastern North Pacific (ENP) gray whales (Eschrichtius robustus) migrate annually between ; foraging grounds in the Arctic and wintering grounds in Baja California (Rice and Wolman ; 1971). Females nurture their newborn calves in protected lagoons in Baja California Sur, ; Mexico, and migrate north with them in the spring of each year. Shore-based counts of ; female gray whales accompanying their calves (i.e., mother-calf pairs) have been conducted ; annually from the Piedras Blancas Lighthouse Station in central California since 1994 with ; the exception of 2020 due to COVID-19. Survey methods were evaluated in detail at the ; outset of the study (Perryman et al. 2002) and both survey methods and the analytical ; approach used to estimate total annual calf production have remained consistent through ; the 2019 survey (Perryman et al. 2021). ; In 2021, Stewart and Weller (2021) presented a new Bayesian modeling approach to ; estimate annual calf production of ENP gray whales. This approach accounted for ; uncertainty during unsampled periods (i.e., evenings, weekends, and during periods of ; unworkable weather). Here we provide estimates of calf production for the 1994-2023 ; period using the Bayesian approach. A comparison of estimates between the methods of ; Perryman et al. (2021) to those used by Stewart and Weller (2021) was provided in Eguchi ; et al. (2022a).
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• Keywords:
  • Southwest Fisheries Science Center
  • Marine Mammal and Turtle Division
  • Gray whales
  • Calf production
• Series:
  NOAA-TM-NMFS-SWFSC ; 685
• DOI:
  https://doi.org/10.25923/e9at-x936
• Format:
  PDF
• Document Type:
  Technical Memorandum
• Place as Subject:
  North Pacific
• License:
  https://creativecommons.org/publicdomain/zero/1.0/
• Rights Information:
  CC0 Public Domain
• Compliance:
  Submitted
• Download URL:
  https://repository.library.noaa.gov/view/noaa/51189/noaa_51189_DS1.pdf
• File Type:
  [PDF - 1.24 MB]
• Collection(s):
  National Marine Fisheries Service (NMFS)
• Main Document Checksum:
  urn:sha256:5ac896e08cadcedaf39278b9573caf968d90547b0527cb3378fae2f42670c607