Mysticete Sounds

Sei whales are the least well known acoustically of all the rorquals, with only two brief descriptions of their calls previously reported. Recordings of low-frequency tonal and frequency swept calls were made near a group of four or five sei whales in waters west of the Antarctic Peninsula on 19 February 2003. These whales also produced broadband sounds which can be described as growls or whooshes. Many of the tonal and frequency swept calls ͑30 out of 68͒ consist of multiple parts with a frequency step between the two parts, this being the most unique characteristic of the calls, allowing them to be distinguished from the calls of other whale species. The average duration of the tonal calls is 0.45± 0.3 s and the average frequency is 433± 192 Hz. Using a calibrated seafloor recorder to determine the absolute calibration of a sonobuoy system, the maximum source level of the tonal calls was 156± 3.6 dB re 1 Pa at 1 m. Each call had different character and there was no temporal pattern in the calling.

Section: Discussionsupporting

confidence: 57%

“…The two extant descriptions ͑Thompson et al, 1979;Knowlton et al, 1991͒ are for sei whales encountered near Nova Scotia in the North Atlantic, where two-part stereotyped pulsive bursts in the 1.5 to 3.5 kHz frequency range were recorded.…”

Section: Introductionmentioning

confidence: 99%

Sei whale sounds recorded in the Antarctic

McDonald

Hildebrand

Wiggins

et al. 2005

“…Only four reports of sei whale calls are currently available. Thompson et al ͑1979͒ described recordings of sei whales obtained in the waters between Nova Scotia and Newfoundland, Canada, as 0.7 s long bursts of seven to ten metallic pulses with peak energy at 3 kHz. Knowlton et al ͑1991͒ described similar 1.4-2.6 s midfrequency vocalizations recorded in waters off southwestern Nova Scotia, Canada that consisted of two bouts of 10-20 frequency-modulated ͑FM͒ 1.5-3.5 kHz sweeps separated by 0.4-1 s. In the Southern Ocean near the Antarctic Peninsula, McDonald et al ͑2005͒ recorded a number of tonal, FM, and broadband calls between 200 and 700 Hz in proximity to sei whales.…”

Section: Introductionmentioning

confidence: 99%

Low frequency vocalizations attributed to sei whales (Balaenoptera borealis)

Baumgartner

Parijs

Wenzel

et al. 2008

Low frequency ͑Ͻ100 Hz͒ downsweep vocalizations were repeatedly recorded from ocean gliders east of Cape Cod, MA in May 2005. To identify the species responsible for this call, arrays of acoustic recorders were deployed in this same area during 2006 and 2007. 70 h of collocated visual observations at the center of each array were used to compare the localized occurrence of this call to the occurrence of three baleen whale species: right, humpback, and sei whales. The low frequency call was significantly associated only with the occurrence of sei whales. On average, the call swept from 82 to 34 Hz over 1.4 s and was most often produced as a single call, although pairs and ͑more rarely͒ triplets were occasionally detected. Individual calls comprising the pairs were localized to within tens of meters of one another and were more similar to one another than to contemporaneous calls by other whales, suggesting that paired calls may be produced by the same animal. A synthetic kernel was developed to facilitate automatic detection of this call using spectrogram-correlation methods. The optimal kernel missed 14% of calls, and of all the calls that were automatically detected, 15% were false positives.

“…Marine mammals produce sounds to transmit information about location, intention, age, sex, reproductive status, and identity of the caller ͑Thompson et al ., 1979;Tyack and Whitehead, 1983;Watkins et al, 1987Watkins et al, , 2000Van Parijs et al, 1999;Tyack and Clark, 2000͒. The odontocete cetaceans use high-frequency biosonar to locate prey and to interrogate their environment ͑Au et al, 1974͒. Most marine mammal species use passive listening to aid in location of prey, avoidance of predators, and navigation ͑Tyack and Clark, 2000͒.…”

Section: Introductionmentioning

confidence: 99%

The effect of a low-frequency sound source (acoustic thermometry of the ocean climate) on the diving behavior of juvenile northern elephant seals, Mirounga angustirostris

Costa

Crocker

Gedamke

et al. 2003

Changes in the diving behavior of individual free-ranging juvenile northern elephant seals, Mirounga angustirostris, exposed to the acoustic thermometry of the ocean climate ͑ATOC͒ sound source were examined using data loggers. Data loggers were attached to the animals and measured swim speed, maximum depth of dive, dive duration, surface interval, descent and ascent rate, and descent and ascent angle along with sound pressure level ͑SPL͒. The ATOC sound source was at a depth of 939 m and transmitted at 195 dB re: 1 Pa at 1 m centered at 75 Hz with a 37.5-Hz bandwidth. Sound pressure levels ͑SPL͒ measured at the seal during transmissions averaged 128 dB and ranged from 118 to 137 dB re: 1 Pa for the 60-90 Hz band, in comparison to ambient levels of 87-107 dB within this band. In no case did an animal end its dive or show any other obvious change in behavior upon exposure to the ATOC sound. Subtle changes in diving behavior were detected, however. During exposure, deviations in descent rate were greater than 1 s.d. of the control mean in 9 of 14 seals. Dive depth increased and descent velocity increased in three animals, ascent velocity decreased in two animals, ascent rate increased in one animal and decreased in another, and dive duration decreased in only one animal. There was a highly significant positive correlation between SPL and descent rate. The biological significance of these subtle changes is likely to be minimal. This is the first study to quantify behavioral responses of an animal underwater with simultaneous measurements of SPL of anthropogenic sounds recorded at the animal.