Abstract:

The Mingan Island Cetacean Study has been conducting biological field research on St. Lawrence blue whales since 1979. Currently, they have photo-identified 384 individuals and determined the gender of 37% through skin biopsy sampling. In a typical field season, approximately 85% of the 60–90 blue whales identified have been seen before, so a larger percentage (65%) have known gender. During four field seasons (1998–2001), 134 h of acoustic recordings were made in the presence of this well-studied population of blue whales. A calibrated omnidirectional hydrophone, suspended from a surface isolation buoy, was deployed from an inflatable boat positioned close to the whales. Simultaneous visual observations were made during the recording sessions, with individual identities confirmed through photo-identification work between sessions. The primary field site for this project was the lower estuary region of the St. Lawrence River , with most recordings made between mid-August and late October. Both infrasonic tonal call sequences as well as aubible downsweep calls were recorded. Temporal and spatial distribution of the two call types will be presented, and possible correlations with behavior and/or social grouping will be discussed. [Work supported by ARL/PSU, NSF, and the American Museum of Natural History.]

Berchok, C.L., Bradley, D.L., Gabrielson, T.B., and Sears, R. 2002. St. Lawrence blue whale ( Balaenoptera musculus ) vocalizations. J. Acoust. Soc. Am. 112, 2400.