Estimation of the feeding record of pregnant Antarctic minke whales (Balaenoptera bonaerensis) using carbon and nitrogen stable isotope analysis of baleen plates

• Published in: Polar biology Vol. 44; no. 3; pp. 621 - 629
• Main Authors: Uchida, Mayuka, Suzuki, Ippei, Ito, Keizo, Ishizuka, Mayumi, Ikenaka, Yoshinori, Nakayama, Shouta M. M., Tamura, Tsutomu, Konishi, Kenji, Bando, Takeharu, Mitani, Yoko
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.03.2021; Springer; Springer Nature B.V
• Subjects: Analysis; Aquatic mammals; Balaenoptera bonaerensis; Baleens; Bayesian analysis; Behavior; Biomedical and Life Sciences; Breeding; Cetacea; Crustaceans; Diet; Ecology; Euphausia superba; Fish; Growth rate; Krill; Latitude; Life Sciences; Marine crustaceans; Marine mammals; Mathematical models; Microbiology; Nitrogen; Oceanography; Oscillations; Pelagic fish; Plant Sciences; Plates; Pregnancy; Pregnant women; Prey; Probability theory; Short Note; Silver; Stable isotopes; Stomach content; Whales; Zoology; Stable isotope analysis; Baleen plate; Antarctic; Feeding record; Antarctic minke whales
• ISSN: 0722-4060; 1432-2056
• DOI: 10.1007/s00300-021-02816-5

Antarctic minke whales ( Balaenoptera bonaerensis ) are migratory capital breeders that experience intensive summer feeding on Antarctic krill ( Euphausia superba ) in the Southern Ocean and winter breeding at lower latitudes, but their prey outside of the Antarctic is unknown. Stable isotope analyses were conducted on δ 13 C and δ 15 N from the baleen plates of ten pregnant Antarctic minke whales to understand the growth rate of the baleen plate and their diet in lower latitudes. Two to three oscillations along the length of the edge of the baleen plate were observed in δ 15 N, and the annual growth rate was estimated to be 75.2 ± 20.4 mm, with a small amplitude (0.97 ± 0.21 ‰). Bayesian stable isotope mixing models were used to understand the dominant prey that contributed to the isotopic component of the baleen plate using Antarctic krill from the stomach contents and reported values of Antarctic coastal krill ( Euphausia crystallorophias ), Antarctic silver fish ( Pleuragramma antarcticum ), Australian krill spp., and Australian pelagic fish spp.. The models showed that the diet composition of the most recent three records from the base of the baleen plates (model 1) and the highest δ 15 N values in each baleen plate (model 2) were predominantly Antarctic krill, with a contribution rate of approximately 80%. The rates were approximately 10% for Antarctic coastal krill and less than 2.0% for the two Australian prey groups in both models. These results suggest that pregnant Antarctic minke whales did not feed on enough prey outside of the Antarctic to change the stable isotope values in their baleen plates.