Short moan call reveals seasonal occurrence and diel-calling pattern of crabeater seals in the Weddell Sea, Antarctica

• Published in: Bioacoustics
• Main Authors: Shabangu, Fannie Welcome, Charif, Russell A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Taylor and Francis 2021
• Subjects: Crabeater seal (Lobodon carcinophaga); Seasonal occurrence; Diel behaviour; Short moan call; Acoustic repertoire; Antarctic; Southern Ocean; Weddell Sea; Weddell; Maud Rise; Moan; Antarc*; Antarctica; Crabeater Seal; Crabeater Seals; Sea ice; South African National Antarctic Programme
• Online Access: http://hdl.handle.net/2263/78809; https://doi.org/10.1080/09524622.2020.1819877

Crabeater seals (Lobodon carcinophaga) are an important component of the Southern Ocean as they are the most abundant pinniped species in this krill-based ecosystem; however, their acoustic repertoire and ecology remain to be fully described. Seasonal occurrence and diel-calling pattern of crabeater seal off the Maud Rise, eastern Weddell Sea, are described using passive acoustic monitoring data collected over 8 months (mid-January to mid-September) in 2014. We describe a new call type of crabeater seals, the short moan call (mean 90% duration: 2.2 ± 0.3 (SD) s, peak frequency: 596.5 ± 109.4 Hz, and frequency range: 122–1024 Hz), which was the only detected call type and 1871 calls were enumerated. Those crabeater seal calls were detected from April until mid-September (with peak in calling around September), which coincided with the appearance of sea ice. Short moan call rates were highest at night in August (i.e., 6.4 calls per minute) and September, and showed no diel variations for April through July. Distance to the sea ice edge and month of the year were the most important predictors of call occurrence and call rates of crabeater seals. This study highlights the Maud Rise as a useful habitat for this species. The South African National Antarctic Programme and the National Research Foundation and South African National Antarctic Programme for funding the SABWP. http://www.tandfonline.comtoc/tbio20 2021-09-21 hj2021 Mammal Research Institute