DataSheet_1_Seasonal gain in body condition of foraging humpback whales along the Western Antarctic Peninsula.docx

• Main Authors: K. C. Bierlich, Joshua Hewitt, Robert S. Schick, Logan Pallin, Julian Dale, Ari S. Friedlaender, Fredrik Christiansen, Kate R. Sprogis, Allison H. Dawn, Clara N. Bird, Gregory D. Larsen, Ross Nichols, Michelle R. Shero, Jeremy Goldbogen, Andrew J. Read, David W. Johnston
• Format: Dataset
• Language: unknown
• Published: 2022
• Subjects: Oceanography; Marine Biology; Marine Geoscience; Biological Oceanography; Chemical Oceanography; Physical Oceanography; Marine Engineering; drones (unmanned aerial vehicles or UAVs); body condition; humpback whale (Megaptera novaeangliae); Western Antarctic Peninsula (WAP); photogrammetry; baleen whales; Bayesian; Antarctic; Antarctic Peninsula; Antarc*; Humpback Whale; Megaptera novaeangliae
• Online Access: https://doi.org/10.3389/fmars.2022.1036860.s001; https://figshare.com/articles/dataset/DataSheet_1_Seasonal_gain_in_body_condition_of_foraging_humpback_whales_along_the_Western_Antarctic_Peninsula_docx/21589209

Most baleen whales are capital breeders that use stored energy acquired on foraging grounds to finance the costs of migration and reproduction on breeding grounds. Body condition reflects past foraging success and can act as a proxy for individual fitness. Hence, monitoring the seasonal gain in body condition of baleen whales while on the foraging grounds can inform how marine mammals support the costs of migration, growth, and reproduction, as well as the nutritional health of the overall population. Here, we use photogrammetry from drone-based imagery to examine how the body condition of humpback whales (Megaptera novaeangliae) changed over the foraging season (November to June) along the Western Antarctic Peninsula (WAP) from 2017 to 2019. This population (IWC stock G) is recovering from past whaling and is growing rapidly, providing an opportunity to study how whales store energy in a prey-rich environment. We used a body area index (BAI) to estimate changes in body condition and applied a Bayesian approach to incorporate measurement uncertainty associated with different drone types used for data collection. We used biopsy samples to determine sex and pregnancy status, and a length-based maturity classification to assign reproductive classes (n = 228; calves = 31, juveniles = 82, lactating females = 31, mature males = 12, mature unknown sex = 56, non-pregnant females = 12, pregnant females = 3, pregnant & lactating females = 1). Average BAI increased linearly over the feeding season for each reproductive class. Lactating females had lower BAI compared to other mature whales late in the season, reflecting the high energetic costs of nursing a calf. Mature males and non-pregnant females had the highest BAI values. Calves and juvenile whales exhibited an increase in BAI but not structural size (body length) over the feeding season. The body length of lactating mothers was positively correlated with the body length of their calves, but no relationship was observed between the BAI of mothers and their calves. ...