The underwater and in-air recordings were used to derive a technique to classify the call types. The in-air recordings demonstrated that both males and females vocalise and often a single seal will string up to 6 call types together in a variety of orders. No 'Trills' were heard by males or females on the ice. The seals lengthened the duration of multiple-element calls when they were 'interrupted' by another calling seal. This suggests that the seals are listening for the calls of conspecifics while they themselves are calling. A pilot project indicated that almost none of the calls are completely masked by other calling seals. The recordings are being used (in association with recordings obtained in later years) to address other aspects of Weddell seal vocal communication. See the link below for public details on this project.

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 and 36 post-submerging sets of calls were analysed with respect to probability of call type occurrence and timing. Dives were 461 plus or minus 259 seconds (mean plus or minus standard deviation). The seal called every 29.7 plus or minus 56.2 seconds throughout a dive. The first call after submerging was usually (n = 29 of 36) a low frequency (less than 0.8 kHz) growl. Three patterns of three- to five-call type sequences were made following 28 of 36 breathing bouts. Call type patterns after submerging exhibited fewer different sequences than those before surfacing (chi-squared = 61.42, DF = 4, p less than 0.000001). The call usage patterns before surfacing were diverse and did not indicate when the seal was going to surface, a time when he would be vulnerable to attack from below. Our findings suggest the hypotheses that territorial male Weddell seals call throughout each dive and use stereotyped call patterns to identify themselves while vocally asserting dominance. This work was completed as part of ASAC project 2122 (ASAC_2122). The fields in this dataset are: Tape number Sequence per tape Sequence entire data Call types Count since last breath Last breathing bout number Count prior to next breath Time in tape (seconds) End time of last breath Start time of next breath Time since dive The 'sequence' relates to the sequence of call types that are given between the end of the last breath of a breathing bout and the beginning of the first breath the next time the seal surfaces to breathe. Essentially the report relates to the stereotyped nature of the call types, especially just after the dominant male dives after finishing breathing. Each time the animal surfaced, that was identified as a breathing bout. They are numbered sequentially. At the very start of the data set the seal had to surface before the breathing bout could be counted (as number 1). This procedure enabled us to identify the order and timing of the calls that occurred immediately before and immediately after each breathing bout. Thus, the 'count prior to the next breath' gives the order of the calls before the seal surfaced to breathe again (third last, second last, last,). The call types were analysed with respect to the following pattern: third last, second last, last, breathing bout, first, second, third, etc. to third last, second last, last, next breathing bout.

Underwater recordings of vocalisations of Weddell seals were obtained at 8 locations within the Vestfold Hills (7) and Larsemann Hills (1). The recordings were made near groups of seals on the ice during the mid to late part of the breeding season. Recordings were obtained using a variety of hydrophones and both Sony Digital Audio Tape (130 during 1992 season) and standard analogue cassette (60 during 1991 season) formats. Over 11,000 vocalizations were analyzed. The calls were classified into 12 major call types (Pahl et al. 1997 Australian Journal of Zoology 45:171-187). The underwater repertoire is different than that of the seals at McMurdo Sound or the Palmer Penninsula (Thomas et al. 1988 Hydrobiologica 165:279-284). The Weddell seals at the Vestfold Hills do not exhibit the between-fjord vocal differences reported by Morrice et al. (1994 Polar Biology 14:441-446). The relative usage of each call type did not vary between the earlier and later recordings (Pahl et al. 1996 Australian Journal of Zoology 44:75-79). The recordings are currently being used to support other studies on Weddell seal vocalizations. Legend for ASAC_556.csv - csv text format. The following legend describes the 39 variables in this file. The codes for some of the variables are presented in the 1997 publication: Pahl, B.C., Terhune, J.M., and Burton, H.R. 1997. Repertoire and geographic variation in underwater vocalisations of Weddell seals (Leptonychotes weddellii, Pinnipedia: Phocidae) at the Vestfold Hills, Antarctica. Australian Journal of Zoology 45: 171-187. The fields in this dataset are: VariableSubject or code 1LOCATION; recording location; see AJZ article, Figure 1 2DATE; reference day, (date of day 1 has been lost) 3YEAR; 1 = 1991, 2 = 1992 4CASSETTE; cassette number, identifies individual recordings 5CALNO; call number, case numbers of each call, sequential 6CTYPE; call type, provisional call type, subjective initial classification (see below) 7NOELM; number of elements (discrete sounds) in the call 8EL_NO; element within that call relating to next 12 variables, for variable 8, only data from the first element is used 9WVFRM; waveform of element, see AJZ article for codes 10CLSHP; call shape, see AJZ article, Figure 2 for codes 11E_D; duration of the first element (seconds) 12IND1; duration of the interval between the end of the first element and the start of the second element (seconds) 13CALLD; total duration of the call (all elements; seconds) 14INCD; duration between sequential calls (seconds) 15O_LAP; overlap, is call overlapped by another call? 0 = no, 1 = yes 16S2STM; unknown measure 17SFREQ; frequency at start of first element (Hz) 18EFREQ; frequency at end of first element (Hz) 19HFREQ; highest frequency of first element (Hz) 20LFREQ; lowest frequency of first element (Hz) 21E_NO; element number, half way through the call. Data for the next 9 variables relate to this element, applies only to multiple element calls 22CLSHP; call shape of the middle element, same code as variable 10 23WVFRM: waveform of the middle element, same code as variable 9 24E_D; duration of the middle element (seconds) 25IND1; duration of the inter-element interval before the middle element 26IND2; duration of the inter-element interval after the middle element 27SFREQ; frequency at start of the middle element (Hz) 28EFREQ; frequency at end of middle element (Hz) 29HFREQ; highest frequency of middle element (Hz) 30LFREQ; lowest frequency of middle element (Hz) 31E_NO; element number of the last element of the call. Data for the next 8 variables relate to this element, applies only to multiple element calls 32CLSHP; call shape of the last element, same code as variable 10 33WVFRM: waveform of the last element, same code as variable 9 34E_D; duration of the last element (seconds) 35IND2; duration of the inter-element interval before the last element 36SFREQ; frequency at start of the last element (Hz) 37EFREQ; frequency at end of last element (Hz) 38HFREQ; highest frequency of last element (Hz) 39LFREQ; lowest frequency of last element (Hz) Codes for call types (variable 6). The provisional call types were amalgamated into 50 call types that were arbitrarily numbered from 201 to 250. These were subsequently classified into 13 broad categories (Pahl et al. 1997). The amalgamation of the provisional call types of variable 6 into the 50 call types presented in Pahl et al. (1997) is as follows: Call TypeProvisional Call Types (variable 6) 2011 7, 24, 36, 72, 31, 40, 73, 77, 107, 110, 31, 136 2023, 46, 54, 128, 33, 13, 140, 10, 25, 9, 139, 88, 46, 27, 126, 67, 91, 27, 126, 135 20359 204113 20514, 48, 69, 64, 49, 19, 92, 43, 75, 127, 99 206122, 124 2072, 41, 58, 93 20847, 138 20962, 132 210102 211115 21221, 23, 45, 35 21368, 80, 84 214114 2154 216118 21752, 78 2185, 6, 11 219104 22017, 22, 65, 97, 32, 26 22128 22283, 100, 101, 111, 105 22329, 30, 42, 51, 44, 94, 95 22487 22512 22682 2278 22818, 20, 57, 108 229109, 119 23034, 70, 130, 53, 121 23163 23298, 120 23389 23490 23556, 117 23671, 106 23785 238103 23974 24096 24176, 123, 133 24281, 86 24315 244112 24538 24679 24739, 127, 129, 55, 60 24816, 37, 50 249116 25066 For additional information or clarification, please contact Dr. J. Terhune, Dept. of Biology, University of New Brunswick, P.O. Box 5050, Saint John, NB, Canada E2L 4L5, terhune@unbsj.ca or +1 506 648 5633. See the link below for public details on this project.