Geographic variations in underwater male Weddell seal Trills suggest breeding area fidelity

• Other Authors: AADC (originator), AU/AADC > Australian Antarctic Data Centre, Australia (resourceProvider)
• Format: Dataset
• Language: unknown
• Published: Australian Ocean Data Network
• Subjects: biota; location; oceans; SEA ICE; EARTH SCIENCE; CRYOSPHERE; SEALS/SEA LIONS/WALRUSES; BIOLOGICAL CLASSIFICATION; ANIMALS/VERTEBRATES; MAMMALS; CARNIVORES; EARTH SCIENCE > BIOSPHERE > ECOSYSTEMS > MARINE ECOSYSTEMS > COASTAL; POPULATION DYNAMICS; BIOSPHERE; ECOLOGICAL DYNAMICS; SPECIES/POPULATION INTERACTIONS; Weddell seal; vocalisation; geographic variation; Leptonychotes weddellii; HYDROPHONES; ACOUSTIC RECEIVERS; FIELD SURVEYS; FIELD INVESTIGATION; AMD/AU; CEOS; AMD; OCEAN > SOUTHERN OCEAN; CONTINENT > ANTARCTICA; GEOGRAPHIC REGION > POLAR; McMurdo Sound; Neumayer; Southern Ocean; Weddell; Antarc*; Antarctica; Sea ice; Weddell Seal; Weddell Seals; walrus*
• Online Access: https://researchdata.ands.org.au/geographic-variations-underwater-area-fidelity/686090; https://data.aad.gov.au/metadata/records/ASAC_1132-2; http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=2495; https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=1132; https://secure3.aad.gov.au/proms/public/projects/report_project_public.cfm?project_no=2122; http://data.aad.gov.au/aadc/portal/download_file.cfm?file_id=2496; http://data.aad.gov.au/aadc/metadata/citation.cfm?entry_id=ASAC_1132-2

The data are measurements relating to the acoustic properties of Weddell seal underwater Trill vocalisations. The measures include a broad classification of the waveform (sinusoidal, frequency modulated or pulsed)at the start and end of the Trill, the duration (milliseconds) and the frequency (Hz) at the beginning, end and at 9 other equally spaced intervals along the call. Trills were recorded in different years from 6 locations around Antarctica. Only Trill vocalisations were analysed because they are only made by males and they have a known territorial defence function. Adult Weddell seals (Leptonychotes weddellii) exhibit site fidelity to where they first breed but juveniles, and perhaps transient adult males, may disperse from their natal location. If there is mixing between adjacent breeding groups, we would expect that common vocalisations would exhibit clinal patterns. Underwater Trill vocalisations of male Weddell seals at Mawson, Davis, Casey, McMurdo Sound, Neumayer and Drescher Inlet separated by ca. 500 to greater than 9,000 km, were examined for evidence of clinal variation. Trills are only emitted by males and have a known territorial defence function. Trills from Davis and Mawson, ca. 630 km apart, were distinct from each other and exhibited the greatest number of unique frequency contour patterns. The acoustic features (duration, waveform, frequency contour) of Trills from Neumayer and Drescher Inlet, ca. 500 km apart, were more distinct from each other than they were from the other four locations. General Discriminant Analysis and Classification Tree Analysis correctly classified 65.8 and 76.9% of the Trills to the correct location. The classification errors assigned more locations to sites greater than 630 km away than to nearest neighbours. Weddell seal Trills exhibit geographic variation but there is no evidence of a clinal pattern. This suggests that males remain close to single breeding areas throughout their lifetime. This work was completed as part of ASAC project 1132 and 2122 (ASAC_1132, ASAC_2122).