Time patterns of sperm whale codas recorded in the Mediterranean Sea 1985–1996

Abstract

A distinctive vocalization of the sperm whale, Physeter macrocephalus (=P. catodon), is the coda: a short click sequence with a distinctive stereotyped time pattern [Watkins and Schevill, J. Acoust. Soc. Am. 62, 1485-1490 (1977)]. Coda repertoires have been found to vary both geographically and with group affiliation [Weilgart and Whitehead, Behav. Ecol. Sociobiol. 40, 277-285 (1997)]. In this work, the click timings and repetition patterns of sperm whale codas recorded in the Mediterranean Sea are characterized statistically, and the context in which the codas occurred are also taken into consideration. A total of 138 codas were recorded in the central Mediterranean in the years 1985-1996 by several research groups using a number of different detection instruments, including stationary and towed hydrophones, sonobuoys and passive sonars. Nearly all (134) of the recorded codas share the same "3+1" (/// /) click pattern. Coda durations ranged from 456 to 1280 ms, with an average duration of 908 ms and a standard deviation of 176 ms. Most of the codas (a total of 117) belonged to 20 coda series. Each series was produced by an individual, in most cases by a mature male in a small group, and consisted of between 2 and 16 codas, emitted in one or more "bursts" of 1 to 13 codas spaced fairly regularly in time. The mean number of codas in a burst was 3.46, and the standard deviation was 2.65. The time interval ratios within a coda are parameterized by the coda duration and by the first two interclick intervals normalized by coda duration. These three parameters remained highly stable within each coda series, with coefficients of variation within the series averaging less than 5%. The interval ratios varied somewhat across the data sets, but were highly stable over 8 of the 11 data sets, which span 11 years and widely dispersed geographic locations. Somewhat different interval ratios were observed in the other three data sets; in one of these data sets, the variant codas were produced by a young whale. Two sets of presumed sperm whale codas recorded in 1996 had 5- and 6-click patterns; the observation of these new patterns suggests that sperm whale codas in the Mediterranean may have more variations than previously believed.

Coda vocalizations recorded in breeding areas are almost entirely produced by mature female sperm whales (Physeter macrocephalus)

“…Pavan et al (2000) recorded codas from males in the Mediterranean Sea. However, the context of the recordings was different from that of our study.…”

“…These intervals are proportional to the physical dimensions of the click-producing apparatus, and thus are monotonically related to the length of the producer (Adler-Fenchel 1980;Møhl et al 1981;Gordon 1991;Pavan et al 2000;Rhinelander and Dawson 2004). By this method, we are able to estimate the size of sperm whales and infer which age and sex classes produce the codas.…”

Review of Underwater and In-Air Sounds Emitted by Australian and Antarctic Marine Mammals

“…Sperm whales have been recorded off the US east coast [324][325][326][327][328], off Nova Scotia [329,330], around the Bahamas [331][332][333], around Bermuda [334], in the Caribbean [335][336][337][338][339], in the Gulf of Mexico [340][341][342][343], in Alaska [344][345][346][347][348], in the northeast Pacific [349], off Japan [350,351] around Hawaii [352], at the Galapagos Islands [173,353,354], at the Azores [355], off Scotland [356], off Norway [357][358][359][360][361], in the Mediterranean [362][363][364][365][366], in the South Pacific [367], in New Zealand [368][369]<...>…”

Off-axis effects on the multipulse structure of sperm whale usual clicks with implications for sound production

“…Despite the potential for acoustic size estimation of sperm whale stocks, the technique has only been employed in a few studies ͑Adler-Fenchel, 1980;Leaper et al, 2002;Pavan et al, 2000;Drouot et al, 2004;Miller et al, 2004;Rhinelander and Dawson, 2004͒. While there may be a number of reasons for this, one likely relates to the fact that recorded sperm whale clicks seldom conform to the clear multipulse structure depicted in textbooks and papers.…”