Hyperoodon Planifrons Research Articles

Odontocetes of the Southern Ocean Sanctuary

Twenty-eight odontocete species were identified as occupying sub-Antarctic and Antarctic habitat covered by the 1994 IWC-established Southern Ocean Sanctuary. Toothed whales evidently play an important part in the Antarctic polar ecosystem. Twenty-two species are autochthonous in showing a regular, apparently year-round, presence in the Sanctuary: Physeter macrocephalus, Kogia breviceps, Orcinus orca, Globicephala melas edwardii, Pseudorca crassidens, Lagenorhynchus cruciger, Lagenorhynchus obscurus, Lissodelphis peronii, Cephalorhynchus commersonii, Cephalorhynchus hectori, Tursiops truncatus, Delphinus delphis, Phocoena dioptrica, Hyperoodon planifrons, Berardius arnuxii, Ziphius cavirostris, Tasmacetus shepherdi, Mesoplodon layardii, Mesoplodon traversii, Mesoplodon grayi, Mesoplodon bowdoini and Mesoplodon hectori. Six species are considered vagrants into the Sanctuary: Kogia sima, Grampus griseus, Steno bredanensis, Mesoplodon peruvianus, Mesoplodon densirostris and Mesoplodon mirus. However, vagrant status of these three mesoplodonts is only provisionally assigned, considering that improved knowledge of diagnostic features of beaked whales should, as in recent years, continue to facilitate at-sea identification. Two species are considered as having a ‘contiguous’ range (records less than 2° north of Sanctuary boundaries): Mesoplodon ginkgodens (at 39°S) and Mesoplodon mirus (at 38°24’S). The habitual southern range of at least four odontocetes extends significantly farther poleward than expected. G. melas edwardii is regularly encountered south of the Antarctic Polar Front, much like M. grayi which is known to reach the Ross Sea ice edge (ca. 67°S). Z. cavirostris and L. obscurus cross the Polar Front occasionally. The distribution of M. peruvianus and M. traversii and their relation to SST are unclear. Their southernmost records, 42°31’S and 44°17’S respectively, may either be extralimital or, more likely, reflect ordinary austral range. Temporally non-aligned distribution patterns of Hyperoodon planifrons in Antarctic and South African waters may suggest stock segregation.

Acoustic detections of beaked whales, narrow-band high-frequency pulses and other odontocete cetaceans in the Southern Ocean using an autonomous towed hydrophone recorder

Encased in a streamlined, flooded housing, a SoundTrap ST300HF hydrophone recording system was towed on voyages to South Georgia Island and the South Sandwich Islands and to the Antarctic Peninsula in December 2019–February 2020. Recordings were analyzed to identify acoustic detections of cetacean species. Acoustically identified species included sperm whales (Physeter macrocephalus), southern bottlenose whales (Hyperoodon planifrons), Arnoux's beaked whales (Berardius arnuxii), killer whales (Orcinus orca), and long-finned pilot whales (Globicephala melas). Acoustic detections also included several recognized types of beaked whale echolocation pulses (BW37/39 and BW58) as well as two likely beaked whale echolocation pulse types that do not match any previous descriptions. Narrow-band high-frequency echolocation signals (NBHF) (typical of porpoises and some dolphin species) were detected in many locations, and one of these coincided with a sighting of hourglass dolphins (Lagenorhynchus cruciger). This study shows the utility of an autonomous towed hydrophone system on a vessel of opportunity to study the distribution of cetaceans in rough seas that are difficult to study by visual survey methods.

Autonomous towed hydrophone system detects many beaked whales and other cetacean species in waters of the Southern Ocean

A SoundTrap ST300HF hydrophone recorder in a streamlined, flooded towbody was towed behind expeditionary tourism vessels on trips to South Georgia and the South Sandwich Islands and to the Antarctic Peninsula in December 2019—February 2020. Recordings were analyzed to identify acoustic detections of cetacean species. Identified species included sperm whales (Physeter macrocephalus) and southern bottlenose whales (Hyperoodon planifrons). Acoustic detections also included echolocation pulses from several previously described beaked whale pulse types (BW37 and BW58) as well as a possibly new type of beaked whale echolocation pulse. Narrow-band high-frequency (NBHF) echolocation signals (typical of porpoises and some dolphin species) were detected at several locations, and one of these coincided with a sighting of hourglass dolphins (Lagenorhynchus cruciger). Unidentified large delphinids were also detected several times. This study shows the utility of a simple towed hydrophone system on a vessel of opportunity to study the distribution of cetaceans in rough seas that are difficult to study by visual survey methods. Additional research is needed to link the unidentified echolocation signals to known species throughout waters of the Southern Ocean.

South Africa’s newly approved marine protected areas have increased the protected modelled habitat of nine odontocete species

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 633:1-21 (2020) - DOI: https://doi.org/10.3354/meps13190 FEATURE ARTICLE South Africa’s newly approved marine protected areas have increased the protected modelled habitat of nine odontocete species Jean Purdon1,*, Fannie Shabangu2, Marc Pienaar3, Michael J. Somers4, Ken P. Findlay5 1Whale Unit, Mammal Research Institute, Department of Zoology and Entomology, University of Pretoria, Pretoria 0002, South Africa 2Fisheries Management Branch, Department of Environmental Affairs, Cape Town 8000, South Africa 3South African Environmental Observation Network, uLwazi Node, Pretoria 0083, South Africa 4Eugène Marais Chair of Wildlife Management, Centre for Invasion Biology, Mammal Research Institute, University of Pretoria, Pretoria 0002, South Africa 5CPUT Research Chair: Oceans Economy, Cape Peninsula University of Technology, Cape Town 8000, South Africa *Corresponding author: purdonjean@gmail.com ABSTRACT: Marine protected areas (MPAs) are important for the preservation of ecosystem functioning, ecosystem services, resilience and biodiversity around the world. In South Africa, the role of MPAs in the protection of cetaceans is poorly understood, a knowledge gap that may affect management decisions and future cetacean conservation. Here, we used presence data of 9 odontocete species (namely southern bottlenose whale Hyperoodon planifrons, common dolphin Delphinus delphis, dusky dolphin Lagenorhynchus obscurus, false killer whale Pseudorca crassidens, Indo-Pacific humpback dolphin Sousa chinensis, Heaviside’s dolphin Cephalorhynchus heavisidii, killer whale Orcinus orca, Risso’s dolphin Grampus griseus and Indo-Pacific bottlenose dolphin Tursiops aduncus) to predict their distribution in the South African exclusive economic zone (EEZ) using ensemble models. The data were collected from various opportunistic, historical and scientific records spanning the period 1957-2014. Up to 9 predictor variables (sea surface temperature, chlorophyll a concentration, salinity, bathymetry, distance to shore, bottom slope, eastward and northward sea water velocity and bioregion) were used in the ensemble model to predict the distributions for each odontocete species. Model results suggest that some of the species’ preferred habitats are partially (i.e. <5% of the distribution) protected by the established MPAs, but the protection area does increase with the recently approved MPAs. This study provides a baseline for the distribution of the 9 odontocete species in relation to the MPAs, which could facilitate the protection and management of these species in the region and help identify important marine mammal areas. KEY WORDS: Habitat modelling · Species distributions · Marine protected areas · Odontocetes · South Africa Full text in pdf format Information about this Feature Article Supplementary material NextCite this article as: Purdon J, Shabangu F, Pienaar M, Somers MJ, Findlay KP (2020) South Africa’s newly approved marine protected areas have increased the protected modelled habitat of nine odontocete species. Mar Ecol Prog Ser 633:1-21. https://doi.org/10.3354/meps13190 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 633. Online publication date: January 09, 2020 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2020 Inter-Research.

Distribution and seasonal abundance of large cetaceans in the Durban whaling grounds off KwaZulu-Natal, South Africa, 1972–1975

Daily charts of the aerial search effort (432 206 nautical miles) of the Union Whaling Company and 1 099 sightings of 10 497 whales were available from 628 flights off Durban between 1972 and 1975. Densities of whales were analysed by month and water depth distribution over the four-year period. Low observed densities of blue Balaenoptera musculus, right Eubalaena australis, sei B. borealis and humpback Megaptera novaeangliae whales most likely resulted from earlier whaling pressure. Seasonality of blue, sei and humpback whales was bimodal, indicative of winter migrations to the north of the Durban whaling grounds, whereas the unimodal seasonality of fin whales B. physalus and minke whales B. bonaerensis or B. acutorostrata suggest the offshore region as the northern terminus of their migrations. Sperm whales Physeter macrocephalus migrate northwards offshore of the KwaZulu-Natal coast in autumn/early winter and southwards in late winter/spring, with larger males migrating later than the smaller males and females. Killer whale Orcinus orca presence was coincident with that of offshore minke whales and the southward migrations of other baleen whales, whereas densities of animals deemed as bottlenose whale Hyperoodon planifrons suggest strong early and late summer seasonal abundance in the offshore region. Such extensive surveys offshore of the KwaZulu-Natal coast are unlikely to be repeated; hence, data-extraction of whaling records provides a valuable source of seasonal and distributional information for marine management.

A rare sighting of a bottlenose whale (Hyperoodon planifrons, Flower, 1882) in shallow waters off southeastern Brazil

59.7’S; 46 o 18.6’W), in waters from 6 to 16 m deep. As it is not usual to record whales so close to the shore in the main entrance of the port of Santos, the crew approached and made a 2-minute video of the specimen using a smartphone. No additional sightings nor stranding events of elusive cetacean species which might have given clues as to the destiny of this specimen were detected in the area in the following days. Based on the images recorded at distances ranging from 2 to 15 m, it was observed that the whale was swimming slowly. During a period of 99 seconds, a total of 11 blows was recorded, with a sequence of 5 surfacing bouts in the first 33 seconds when the boat came very close, and three blows within a period of 8 seconds before the whale dived for the remaining 35 seconds prior to the end of the recording. Images showed part of the whale’s body, from the forehead to the dorsal fin, closer glimpses of the forehead itself, its dorsum, the flukes from behind and the above-mentioned dive. These images allowed the authors to evaluate several details of the specimen’s morphology and color patterns, which were used for the identification of the species as southern bottlenose whale, Hyperoodon planifrons. The clues used to identify the species were

Antarctic beaked whale echolocation signals near South Scotia Ridge

Marine Mammal ScienceVolume 31, Issue 3 p. 1265-1274 Notes Antarctic beaked whale echolocation signals near South Scotia Ridge Jennifer S. Trickey, Corresponding Author Jennifer S. Trickey Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California, 92093-0205 U.S.ACorresponding author (e-mail: [email protected]).Search for more papers by this authorSimone Baumann-Pickering, Simone Baumann-Pickering Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California, 92093-0205 U.S.ASearch for more papers by this authorJohn A. Hildebrand, John A. Hildebrand Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California, 92093-0205 U.S.ASearch for more papers by this authorMaria Vanesa Reyes Reyes, Maria Vanesa Reyes Reyes Fundación Cethus, Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, ArgentinaSearch for more papers by this authorMariana Melcón, Mariana Melcón Fundación Cethus, Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, ArgentinaSearch for more papers by this authorMiguel Iñíguez, Miguel Iñíguez Fundación Cethus, Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, Argentina and Whale and Dolphin Conservation, Cap., Bermudez 1598 (B1636EMB), Olivos, Provincia de Buenos Aires, ArgentinaSearch for more papers by this author Jennifer S. Trickey, Corresponding Author Jennifer S. Trickey Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California, 92093-0205 U.S.ACorresponding author (e-mail: [email protected]).Search for more papers by this authorSimone Baumann-Pickering, Simone Baumann-Pickering Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California, 92093-0205 U.S.ASearch for more papers by this authorJohn A. Hildebrand, John A. Hildebrand Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Drive, La Jolla, California, 92093-0205 U.S.ASearch for more papers by this authorMaria Vanesa Reyes Reyes, Maria Vanesa Reyes Reyes Fundación Cethus, Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, ArgentinaSearch for more papers by this authorMariana Melcón, Mariana Melcón Fundación Cethus, Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, ArgentinaSearch for more papers by this authorMiguel Iñíguez, Miguel Iñíguez Fundación Cethus, Monteverde 3695 (B1636AEM), Olivos, Provincia de Buenos Aires, Argentina and Whale and Dolphin Conservation, Cap., Bermudez 1598 (B1636EMB), Olivos, Provincia de Buenos Aires, ArgentinaSearch for more papers by this author First published: 02 April 2015 https://doi.org/10.1111/mms.12216Citations: 6Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume31, Issue3July 2015Pages 1265-1274 RelatedInformation

Stomach Contents of a Cuvier's Beaked Whale (Ziphius cavirostris) Stranded in Monterey Bay, California

From 1942 to 2010 there were 23 reported strandings of Cuvier’s Beaked Whale, Ziphius cavirostris (Odontoceti: Ziphiidae), in the Pacific Northwest (Oregon and Washington), and 25 reported strandings in California between 1982 and 2010 (Moore and Barlow 2013). Although Z. cavirostris appears to be the most cosmopolitan of the beaked whales, occurring in all oceans except in high polar regions (Leatherwood and Reeves 1983; Heyning 1989), global phylogenetic analyses reveal low maternal gene flow among populations confined to isolated ocean basins (Dalebout and others 2005). Extensive surveys throughout the California Current System (CCS) show that Z. cavirostris is distributed offshore over the continental slope, occurring more frequently closer to shore and aggregated in areas of complex bathymetry (for example, Monterey Bay, California and within the Southern California Bight, see Fig. 2 in Moore and Barlow 2013). In the northern CCS, Moore and Barlow (2013) estimated that the Z. cavirostris population likely has decreased by approximately 30% from 10,771 in 1991 to approximately 7550 individuals in 2008, and they suggested that one potential cause could be ecosystem change, thus highlighting the need for additional information on food habits. Heyning (1989) first summarized prey information for Z. cavirostris from around the world, a list that included 10 cephalopod families (16 genera), gadiform and atheriniform fishes, and 2 accounts of crustacean prey. Santos and others (2001) reported prey remains from 3 Z. cavirostris stranded in the eastern Atlantic and provided a review of known prey remains for the species. MacLeod and others (2003) extended the review of Santos and others (2001) to include comparison of Z. cavirostris with 2 additional beaked whales: Mesoplodon spp. and Hyperoodon planifrons. Combining these records with 7 Z. cavirostris stomachs evaluated by Santos and others (2007), the known diet of Z. cavirostris is based on prey remains recovered from only 45 individuals world-wide; diets consisted of 46 cephalopod species (15 families), infrequent crustacean remains, and rare representation among mostly unidentified fishes (MacLeod and others 2003). Compared with records from the Atlantic, food habits of Z. cavirostris off Alaska and in the eastern North Pacific are less well known (n 5 5 individuals, and only 1 from California). Fiscus (1997) identified 6 cephalopod families (11 genera) from a subset of the stomach remains collected and described by Kenyon (1961) from a mature female Z. cavirostris that stranded in March 1959 on Amchitka Island, Aleutian Islands, Alaska. Foster and Hare (1990) identified 3 of the same cephalopod families (4 genera) as reported by Fiscus (1997) from a Z. cavirostris stranded in Kodiak, Alaska. In the Gulf of Mexico, Fertl and others (1997) identified a single beak of Loligo peali from an individual that stranded in Texas. An adult female Z. cavirostris (Moss Landing Marine Laboratory Museum [MLMLM] #499, standard length 600 cm) stranded dead on 15 January 1998 at Marina State Beach, California (UTM: Zone 10S, 607191E, 4062264N, WGS84). During a 2-d field necropsy, to minimize the loss of contents, we tied-off both the esophageal and duodenal ends of the stomach before removing it on 16 January 1998. Prey remains were also collected from the whale’s oral cavity. The stomach contents from 5 pyloric compartments (see Kenyon 1961 for a description of the stomach of an adult female Z. cavirostris) were gently rinsed and sifted through a 500-mm sieve. Cephalopod remains (whole beaks, beak fragments, and eye lenses) and fish remains (bones and eye lenses) were preserved in 50% isopropyl alcohol and fish otoliths were stored dry. Cephalopods were identified to lowest taxon using the GENERAL NOTES

Beaked whale strandings on the Falkland Islands and South Georgia, South Atlantic Ocean, between 1866 and 2008

Records of beaked whales stranded in the Falkland Islands and at South Georgia were collated for the period 1866 to 2008. Thirty-eight records, involving at least seven species in four genera, were documented. Strap-toothed whales (Mesoplodon layardiiGray, 1865) were the most common species with 11 records, including two neonates. Andrews' beaked whales (M. bowdoiniAndrews, 1908), Arnoux's beaked whales (Berardius arnuxiiDuvernoy, 1851), Cuvier's beaked whales (Ziphius cavirostrisGray, 1823), Gray's beaked whale (M. grayivan Haast, 1876), Hector's beaked whales (M. hectoriGray, 1871) and southern bottlenose whales (Hyperoodon planifronsFlower, 1882) were recorded on three to five occasions. In several cases, records suggested potential temporal changes in range. For example, Arnoux's beaked whale has not been recorded in the Falkland Islands since 1965, whilst Gray's beaked whale was not recorded prior to 1981, and Andrews' beaked whale was not recorded before 1987. Although the number of records for each species is low, this could reflect changes in water temperatures and/or prey availability. Overall, this study confirms that the Falkland Islands–Tierra del Fuego region is one of the world's key areas for beaked whales.

Spatial distribution patterns of southern bottlenose whales, Hyperoodon planifrons, near the South Shetland Islands, Antarctica

Spatial distribution patterns of southern bottlenose whales, Hyperoodon planifrons, near the South Shetland Islands, Antarctica

Nouvelles données sur les cétacés des îles Kerguelen / New data on cetaceans of the Kerguelen Islands

RésuméDes observations nouvelles et quelques échouages complètent le premier bilan faunistique établi en 1989 pour les îles Kerguelen. Aux neuf espèces identifiées précédemment ( Eubalaena glacialis , Balaenoptera acutorostrata , Megaptera novaeangliae , Physeter macrocephalus , Mesoplodon layardii , Cephalorhynchus commersonii , Lagenorhynchus cruciger , Orcinus orca , et Globicephala melas ) s'ajoutent, grâce à des échouages, deux nouvelles espèces: Ziphius cavirostris et Hyperoodon planifrons . En outre, la présence occasionnelle de Phocoena dioptrica est confirmée. L'événement le plus marquant est cependant le grand nombre d'observations (n=1649) de cachalots ( Physeter macrocephalus ) faites depuis 1989 au delà du plateau des îles, dans une zone peu fréquentée autrefois par les bateaux de pêche. Pour le dauphin de Commerson ( Cephalorhynchus commersonii ), espèce la plus commune, des données biologiques et écologiques s'ajoutent aux données faunistiques. Nous faisons également état, pour trois espèces ( Physeter macrocephalus , Orcinus orca , et Globicephala melas ), d'interactions avec la pêcherie à la palangre de la légine australe ( Dissostichus eleginoides ).

A southern bottlenose whale examined in the Antarctic

This paper mainly concerns the dissection of a lactating female southern bottlenose whale Hyperoodon planifrons especially shot and worked up for the author in the Antarctic 61°09'S, 86°44'E on 10 March 1948. The skeleton is in the British Museum (Natural History). A comparison with what is known of the female northern bottlenose whale H. ampullatus shows no differences in morphometry, body colour, external characters, digestive system and reproductive system, parasites and the vertebral formula and the digital formula of the flipper. There remain acknowledged differences in the skull which may be reduced or perhaps even disappear when further comparisons are attempted between skulls from males and females of similar ages. There is also the confusion when identifying ziphiid whales at sea. These observations have suggested to the author that there may be only one Hyperoodon species with a continuous distribution north and south. But Dalebout et al. (2004), applying DNA sequencies in molecular taxonomy, have now shown that all 21 species of ziphiid whales are valid.

APPEARANCE, DISTRIBUTION, AND GENETIC DISTINCTIVENESS OF LONGMAN'S BEAKED WHALE, INDOPACETUS PACIFICUS

AbstractLongman's beaked whale, Indopacetus pacificus, was known previously from only two skulls. Here we describe four new specimens of this species from strandings in the western and central Indian Ocean. Two juveniles, previously misidentified from external morphology as Hyperoodon planifrons, were identified as I. pacificus through diagnostic characteristics of mitochondrial (mt) DNA sequences derived from the holotype of this species. Images of the external appearance and teeth of the species are presented for the first time. Comparison of the color pattern of these new specimens with that of “tropical bottlenose whales” sighted in the tropical Indian and Pacific oceans confirm that those unidentified whales represent I. pacificus. Moore (1968) erected a new genus, Indopacetus, for this species (described initially as Mesoplodon pacificus) based primarily on cranial morphology. Phylogenetic analyses of short mtDNA fragments available from the specimens known to date were unable to resolve the validity of this genus. However, the diagnostic osteological features highlighted by Moore (1968) for Indopacetus were also observed in the new specimens. Rib count and number of fused cervical vertebrae may also be diagnostic. Rostrum depth at mid‐length and melon shape further distinguish this species from Mesoplodon beaked whales. As such, we see no reason on morphological grounds to overturn Moore's (1968) proposal that Longman's beaked whale is sufficiently distinct to be afforded its own genus.

Review of Data on Diets of Beaked Whales: Evidence of Niche Separation and Geographic Segregation

This study reviewed published data on dietary preferences of beaked whales (Ziphiidae) from stomach contents analysis. Detailed data were only available for three of the six beaked whale genera (Hyperoodon, Mesoplodon and Ziphius). Stomach samples of these three beaked whale genera primarily contained cephalopod and fish remains, although some also contained crustaceans. Mesoplodon spp. were found to contain the most fish, with some species containing nothing but fish remains, while the southern bottlenose whale (Hyperoodon planifrons) and Cuvier's beaked whale (Ziphius cavirostris) rarely, if ever, contained fish. Of cephalopods identified, Histioteuthid, Gonatid, Cranchiid and Onychoteuthid species usually contributed most to prey numbers and biomass for all beaked whale genera. There was a wide range of species and families of cephalopods recorded from stomach contents, with no obvious preference for bioluminescent prey species, vertical migrating prey species or prey species with specific body compositions. Whales of the genus Mesoplodon generally contained smaller prey, such as cephalopods under 500 g in weight, compared with other beaked whales. Hyperoodon and Ziphius frequently contained much larger cephalopods with many important prey species having a mean weight of over 1000 g. This suggests that Mesoplodon occupies a separate dietary niche from Hyperoodon and Ziphius, which may be an example of niche segregation. In contrast, Hyperoodon and Ziphius appear to occupy very similar dietary niches but have geographically segregated distributions, with Hyperoodon occupying cold-temperate to polar waters and Ziphius occupying warm-temperate to tropical waters.

Results of passive acoustic surveys for odontocetes in the Southern Ocean

Passive acoustic surveys for cetaceans were carried out from the British Antarctic Survey research vessel James Clark Ross in the region of South Georgia in the austral summer of 1998/99 and also during the IWC/CCAMLR collaborative survey in January/February 2000. The acoustic surveys were conducted concurrently with visual observations. A simple two element hydrophone array, sensitive to frequencies of between 300Hz and 24kHz, was towed on a 400m cable astern of the vessel. The total combined acoustic effort for the two surveys was 569 hours along 11,491km (6,205 n.miles) of trackline. On both surveys, stereo recordings were made for 30 seconds every two minutes. Acoustic detections were made of sperm, killer, pilot and southern bottlenose whales and hourglass dolphins. Reliable density estimates were only possible for sperm whales but the data on other species provide useful indications of relative distribution. A total of 42 individual sperm whales were detected and of these 33 were located by crossing bearings derived acoustically from several points along the trackline. Analysis of perpendicular distances pooled across both surveys gave an estimated strip half width of 8.0km (95% CI 6.4-9.9km) giving an overall density estimate for sperm whales of 0.13 and 0.19 whales per 1,000km2 from the 1998/99 and 2000 surveys, respectively. The methods supported estimates of sperm whale density using standard line-transect analyses based on perpendicular distances. The need to filter sounds below 300Hz to reduce ship noise largely precluded monitoring for mysticete vocalisations.

Molecular genetic identification of southern hemisphere beaked whales (Cetacea: Ziphiidae).

To assist in the species-level identification of stranded and hunted beaked whales, we compiled a database of 'reference' sequences from the mitochondrial DNA control region for 15 of the 20 described ziphiid species. Reference samples for eight species were obtained from stranded animals in New Zealand and South Australia. Sequences for a further seven species were obtained from a previously published report. This database was used to identify 20 'test' samples obtained from incompletely documented strandings around New Zealand. Analyses showed that four of these 'test' specimens (20%) had initially been misidentified. These included two animals of particular interest: (i) a Blainville's beaked whale (Mesoplodon densirostris), the first record of this species in New Zealand waters; and, (ii) a juvenile Andrews' beaked whale (Mesoplodon bowdoini), a species known from just over 20 strandings worldwide. A published sequence from a beaked whale product purchased in the Republic of Korea was identified as a Cuvier's beaked whale (Ziphius cavirostris). Levels of intra- and interspecific variation were compared to determine the potential for misidentification when the database or taxonomy is incomplete. Intraspecific variation was generally < 2%, and interspecific divergence was generally > 4.7%. Exceptions were within-species variation in Hyperoodon planifrons, southern bottlenosed whale (4.12%), which exceeded the variation between the two species of Berardius (3.78%), and variation between the two specimens assigned to M. hectori, Hector's beaked whale (7.14%). The latter case appears to be an error in species identification, and could represent the discovery of a new species of beaked whale.

The diet of strap‐toothed whales (Mesoplodon layardii)

The food habits of strap‐toothed whales (Mesoplodon layardii) were examined in detail using stomach contents from 14 stranded whales found on South African and New Zealand coasts. Although a few unidentified fish otoliths and crustacean remains were found in two of these stomachs, 24 species of oceanic squids (some of which occur at a great depth) accounted for 94.8% of counted prey items (n= 232).Histioteuthis sp. and Taonius pavo were the predominant prey species (25.0 and 17.2% by number, 21.4 and 19.9% by mass, respectively). The presence of sub‐Antarctic squid species suggested a northward migration to South African waters in late summer/autumn. Prey sizes were compared between males with fully grown strap‐teeth and females/immature males without erupted teeth, using dorsal mantle lengths (DML) and weights of squids estimated from beak measurements. Although females/immature males ate longer squids than males, there was no significant difference in the estimated weights of squids eaten by the two groups. The presence of fully‐erupted teeth in adult males, therefore, did not seem to influence the size of prey ingested, even though an adult male could only open its jaws about half as wide as a female. In general, the sizes of cephalopods eaten by strap‐toothed whales were not significantly different from those eaten by smaller odontocetes, such as spotted dolphins and dwarf sperm whales, but were significantly smaller than those eaten by larger odontocetes, such as false killer, long‐finned pilot, Cuvier's beaked, and southern bottlenose whales.

Current status of Odontocetes in the Antarctic

The current status of Antarctic Odontocetes – sperm whales Physeter catodon, killer whales Orcinus orca, long-finned pilot whales Globicephala melaena, hourglass dolphins Lagenorhynchus cruciger and poorly known species of beaked whales (family Ziphiidae)–were studied in Anatarctic waters using data gathered in sighting surveys conducted from 1976/77 to 1987/88. Temporal variation in density demonstrated the different migration patterns by species, especially between sperm whale and killer whale. Spatial distributions during mid-summer demonstrated different peaks of occurrence for each species by latitude that suggest possible segregation between the species. Killer whales occur mainly in the very southernmost areas, sperm whales in the southern half of the study area, beaked whales (mostly southern bottlenose whales Hyperoodon planifrons) ranged over a wide area, and long-finned pilot whales and hourglass dolphins were mainly in the northern regions of Antarctic waters. Several longitudinal peaks of occurrence and apparent distribution gaps were identified for sperm, beaked and killer whales. Abundance estimates for south of the Antarctic Convergence in January are based on line transect theory and were 28 100 animals (coefficient of variation CV 0.18) sperm whales, 599 300 (0.15) beaked whales (mostly southern bottlenose whales), 80 400 (0.15) killer whales, 200 000 (0.35) long-finned pilot whales, and 144 300 (0.17) hourglass dolphins. Based on this, biomass of these species were estimated as 0.77 (sperm whales), 2.70 (beaked whales), 0.32 (killer whales), 0.16 (long-finned pilot whales) and 0.01 (hourglass dolphins) million tonnes. Consumption of food (mostly squid) by the Odontocetes is estimated as 14.4 million tonnes with 67% of the total consumed by beaked whales. Indirect consumption of Antarctic krill through the predation of squid by beaked whales is estimated to be c. 24 million tonnes. This value is similar to the estimate of krill consumption by penguins in the Antarctic (33 million tonnes). Odontocetes, especially southern bottlenose whales, are suggested to have a much greater role in the Antarctic ecosystem than has previously been considered.

Relative abundance and behavior of marine mammals exposed to transmissions from the Heard Island Feasibility Test.

The Heard Island Feasibility Test source transmitted a hum at 209-220 dB re: 1 microPa at 175-m depth, centered on 57 Hz with a maximum bandwidth of 30 Hz for 1 h of every 3. Experienced marine mammal observers conducted line-transect surveys and monitored marine mammal behavior visually and acoustically in a 70 x 70 km square centered on the transmission site. Thirty-nine groups of cetaceans and 19 of pinnipeds were sighted from both vessels before the start of transmissions. Thirty-nine groups of cetaceans and 23 of pinnipeds were sighted during transmissions. Blue (Balaenoptera musculus), fin (B. physalus), and sperm (Physeter macrocephalus) whales were sighted during the base line period; blue, sperm, and possibly sei (B. borealis) whales were sighted during the transmission period. More schools of hourglass dolphins (Lagenorhynchus cruciger) were sighted during transmissions, but fewer groups of pilot whales (Globicephala melas), southern bottlenose whales (Hyperoodon planifrons), and minke whales (B. acutorostrata). The density of all cetaceans was 0.0157 groups/km2 before the transmissions and 0.0166 groups/km2 during. Antarctic fur seals (Arctocephalus gazella) and southern elephant seals (Mirounga leonina) were seen, but not in sufficient numbers to estimate abundance. One blue whale tracked before, during and after a transmission changed respiration and reorientation rates, but did not avoid the source detectably. Sperm whales and pilot whales were heard in 23% of 1181 min of baseline acoustic surveys; but in none of 1939 min during the transmission period. Both species were heard within 48 h after the end of the test.

Cephalopods in the diets of three odontocete cetacean species stranded at Tierra del Fuego, Globicephala melaena (Traill, 1809), Hyperoodon planifrons Flower, 1882 and Cephalorhynchus commersonii (Lacepede, 1804)

Cephalopod remains from the stomachs of four pilot whales Globicephala melaena (Traill, 1809), two bottlenose whales Hyperoodon planifrons Flower, 1882 and eight Commerson's dolphins Cephalorhynchus commersonii (Lacepede, 1804) stranded in Tierra del Fuego, Argentina were identified and measured. A total of 3365 lower beaks (mandibles) were identified and measured and from the rostral, crest and hood length, total wet and dry mass, mean mass and mean mantle length for each taxon were estimated. Over 68% of the cephalopods eaten by the pilot whales and all cephalopods eaten by the bottlenose whales were oceanic squid species (oegopsids). The Commerson's dolphins had only eaten shelf species of the families Loliginidae (97.5%) and Octopodinae (2.5%). Sixteen cephalopod families comprising 23 species were represented. In samples from Globicephala melaena, Loligo gahi represented 31% by number and 7.1% by estimated dry mass, Histioteuthis eltaninae, 29% by number and 4.9% by dry mass and the onychoteuthid Moroteuthis ingens 17.2% by number and 51.5% by dry mass. In samples from Hyperoodon planifrons, Histioteuthis eltaninae represented 24.0% of cephalopods by number but only 5.2% by dry mass, Taonius pavo 53% by number but only 2.5% by dry mass and the large onychoteuthid Kondakovia longimana only 2.5% by number but 65.8% by dry mass. In samples from Cephalorhynchus commersonii, the neritic Loligo gahi contributed 97.4% by number and 97% by dry mass and a neritic octopodinid contributed the rest of the cephalopod part of the diet. While the cephalopods contributed the major part of the diets of these particular cetaceans, other remains included fish and polychaete worms.