| Summary: | Progress Code: completed Statement: Paraphrased from the Materials and Methods of the referenced paper: In early December 1997, we conducted an opportunistic study of the transmission of underwater calls through sea ice. Simultaneous recordings were made underwater and above the ice near a breathing hole. A male seal (identified by his use of trills) frequented the breathing hole during the two days that recordings were obtained. In addition to recording sound levels of the underwater calls just above the ice, the in-air microphone recorded the breathing sounds when the seal surfaced in the hole. it seemed likely that all of the recordings were from a single adult male Weddell seal. Recordings were made on landfast sea ice (68.5699 degrees S, 77.9266 degrees E), 1.55km from the shoreline of Davis Station, Eastern Antarctica, on 1 and 8 December 1997. The water depth was 23 m. The ice in this area had been broken up and refrozen following the arrival of the R.S.V. Aurora Australis to the station two months earlier. Recordings were made on an opportunistic basis at two different breathing holes (one per day). Simultaneous recordings in air (using a Radio Shack 33-2050 sound level meter as a microphone) and underwater (Bruel and Kjaer 8100 hydrophone with a Bruel and Kjaer 2635 charge preamplifier) were made using a Sony TCD-D7 DAT recorder. The microphone was 1.0 to 3.0 m from the breathing hole, and the hydrophone was deployed through the breathing hole to a depth of 3.0 to 3.8 m. To reduce possible human disturbance, 2 hour DAT tapes were used and after the equipment was operating, the observer left the area. From the abstract of the attached paper: Underwater calling behaviour between breathing bouts of a single adult male Weddell seal (Leptonychotes weddellii) was examined with respect to call type and timing late in the breeding season at Davis Station, Antarctica. Underwater calls and breathing sounds were recorded on 1 and 8 December 1997. Thirty-seven sequences of calls prior to surfacing to breathe ...
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