Whales Off Research Articles

Vocalizations produced by southern right whale (Eubalaena australis) mother-calf pairs in a calving ground off Brazil.

Aiming to gather information on southern right whale (Eubalaena australis) mother-calf pairs' vocal behavior, archival acoustic recorders were deployed at a calving area off Brazil. Manual inspection of spectrograms revealed seven call classes: upcall, downcall, down-upcall, tonal variable, tonal constant, hybrid, and pulsive calls, which are consistent with those previously described for this species in Argentina. Gunshots and warbles, vocalizations described from other right whale species, were not detected. Mean values of start, end, maximum, minimum and peak frequencies, frequency bandwidth and duration were calculated for each call class. Start and end frequencies, frequency bandwidth and duration of upcalls recorded off Brazil were compared to those from other right whale populations and species. Only mean duration of upcalls from Brazil were significantly different from upcalls from all other populations. Differences in call duration may be driven by differences in demographic factors or background noise features among study areas. The repertoire characterization presented in this study will contribute to increase the utility of passive acoustic monitoring as a tool for conservation and research of southern right whales off Brazil as it provides important baseline information on the vocal behavior of this species.

Southern right whales (Eubalaena australis) off Torres, Brazil: group characteristics, movements, and insights into the role of the Brazilian-Uruguayan wintering ground

Abstract The southern right whale (SRW), Eubalaena australis, was heavily depleted by the whaling in the Southern Hemisphere. In the southwestern Atlantic, studies on SRWs have been concentrated in two main breeding grounds: Península Valdés, Argentina (~42°′S) and Santa Catarina (SC) State, Brazil (~28°′S). To better understand the ecology of SRWs in the region located between these breeding grounds, shore-based surveys were carried out off Torres (29°19′S, 49°43′W), Rio Grande do Sul (RS). Whales were observed in the area between July and October with peaks in August and September. Group sizes were relatively small (x̅=1.6; range=1–3). Distribution in relation to distance from the coast varied from 0.5 to 8.9 km (median=1.9 km). Unlike in other areas, mother-calf pairs were not observed to occur in shallower waters more often than unaccompanied whales. Mother-calf pairs presented northbound movements to SC more frequently than unaccompanied whales. A comparison of the present data with those from Uruguay and SC revealed that SRWs of different gender/reproductive status may use distinctively the eastern coast of South America. Within these regions, the proportion of mother-calf pairs increases progressively as latitude decreases (from 8% in Uruguay to 58.5% in SC), while the proportion of unaccompanied SRWs presents an opposite trend. This study indicates that RS is an important area for reproduction of SRWs because the three phases (birth, nursing, and mating) proposed for a breeding ground occur there.

Editorial January 2016.

Royal Society Open Science provides an exciting new avenue for researchers across all scientific disciplines to publish their research. It offers a range of innovative features backed by one of the world's most respected scientific institutions, so I was delighted to be invited to become the first Editor-in-Chief. The key features that make Open Science different are:

Occurrence, distribution and behaviour of Bryde's whales (Cetacea: Mysticeti) off south-east Brazil

Bryde's whales are among the lesser known balaenopterids found in Brazilian waters, as well as globally. At the beginning of this project, only occasional sightings of this species were identified off the coast of São Paulo State. In this paper, we present the results of our investigations into the occurrence and behaviour of Bryde's whales along the São Paulo coast, both inside and outside the Marine State Park of Laje de Santos, as a contribution to biological and behavioural knowledge of Bryde's whales under the conservation scope. Sighting surveys were conducted from January 2003 to July 2005 in coastal and oceanic areas. During the survey, 42 sightings were made, totalling 71 individuals, between the isobaths of 20 and 3000 m. Sightings and individual rates were higher in coastal areas during the summer season. Different kinds of behaviour were observed in coastal and oceanic areas. At the 1200 m isobath, notable social interactions were observed in which four adult individuals performed breaching – the first report of this behavioural pattern for Brazil. Results suggest that Bryde's whales possibly use coastal areas for feeding and may migrate to oceanic areas for breeding, thus providing important aspects that must be considered for the proper management of Marine Protected Areas and for oceanic areas, especially considering the intensive and continuous increase of oil and gas exploitation activities in those areas. Data reported here, therefore, constitute a significant contribution in Bryde's whale research and to cetacean conservation efforts in Brazil.

Omura's whale off West Africa: autochthonous population or inter-oceanic vagrant in the Atlantic Ocean?

ABSTRACTThe surveillance of marine mammal strandings within the framework of a biomonitoring scheme for the Mauritanian coast led to the discovery in 2013 of a 3.98 m long, juvenile rorqual Balaenoptera sp. in an advanced state of decomposition near Chott Boul (16°32.488′N, 016°27.0317′W). Photographs and skin samples were taken, but the specimen could not be collected. Based on limited morphological evidence, only Balaenoptera edeni and B. omurai were plausible. Sequences of three mtDNA regions, i.e. parts of the cox1 and the cytb genes as well as the D-loop, for a total of 2636 bp (> 16% of the mitogenome) identified the specimen as an Omura's whale, B. omurai, the first record in the Atlantic Ocean and at least 11,400 km away from its closest known range in the SW Indian Ocean (Madagascar). The question of whether the specimen is a vagrant or belongs to an unrecognized Atlantic population is discussed. Advection by currents or transport on a ship's bow bulb following collision are discarded. Circumstances (juvenile status, great distance from Indo-Pacific, necessary inter-oceanic passage through cold temperate waters) may slightly favour the hypothesis that B. omurai, if rare, could be autochthonous in the Atlantic. Beach surveys remain a useful tool to assess trends in cetacean species composition, to detect unusual mortality events and to help assess the impacts of anthropogenic activities. This is particularly applicable to remote areas where the marine mammal fauna is poorly known and where fisheries effort is high, such as the Mauritanian coast.

Omura's whales (Balaenoptera omurai) off northwest Madagascar: ecology, behaviour and conservation needs.

The Omura’s whale (Balaenoptera omurai) was described as a new species in 2003 and then soon after as an ancient lineage basal to a Bryde’s/sei whale clade. Currently known only from whaling and stranding specimens primarily from the western Pacific and eastern Indian Oceans, there exist no confirmed field observations or ecological/behavioural data. Here we present, to our knowledge, the first genetically confirmed documentation of living Omura’s whales including descriptions of basic ecology and behaviour from northwestern Madagascar. Species identification was confirmed through molecular phylogenetic analyses of biopsies collected from 18 adult animals. All individuals shared a single haplotype in a 402 bp sequence of mtDNA control region, suggesting low diversity and a potentially small population. Sightings of 44 groups indicated preference for shallow-water shelf habitat with sea surface temperature between 27.4°C and 30.2°C. Frequent observations were made of lunge feeding, possibly on zooplankton. Observations of four mothers with young calves, and recordings of a song-like vocalization probably indicate reproductive behaviour. Social organization consisted of loose aggregations of predominantly unassociated single individuals spatially and temporally clustered. Photographic recapture of a female re-sighted the following year with a young calf suggests site fidelity or a resident population. Our results demonstrate that the species is a tropical whale without segregation of feeding and breeding habitat, and is probably non-migratory; our data extend the range of this poorly studied whale into the western Indian Ocean. Exclusive range restriction to tropical waters is rare among baleen whale species, except for the various forms of Bryde’s whales and Omura’s whales. Thus, the discovery of a tractable population of Omura’s whales in the tropics presents an opportunity for understanding the ecological factors driving potential convergence of life-history patterns with the distantly related Bryde’s whales.

Bryde's whale (Cetartiodactyla: Balaenopteridae) occurrence and movements in coastal areas of southeastern Brazil

Bryde's whales, Balaenoptera edeni Anderson, 1879, were observed on 17 occasions (N = 21 surveys) in the coastal waters off Rio de Janeiro in southeastern Brazil during austral summer through autumn 2014. Five whales were individually identified using photo-identification techniques. The mean interval between resightings for all individuals was 12.8 days, with a minimum of one day and a maximum of 48 days. The comparison between the catalogs of Bryde's whales off Rio de Janeiro and the Cabo Frio region revealed matches for three individuals. The resightings show movements of up to 149.6 km along the coastal waters off the state of Rio de Janeiro. Most of the observations consisted of solitary individuals (82.3% of sightings). Feeding was the predominant behavior observed (47%), followed by milling (35.3%) and travelling (17.6%) in waters up to 48 m deep. Direct observations resulted in the addition of new prey, such as snubnose anchovy, Anchoviella brevirostris (Gunther, 1868) and white snake mackerel, Thyrsitops lepidopoides (Cuvier, 1832), to the known diet of the Bryde's whale. A long time series of photo-identification efforts in the Rio de Janeiro, the Cabo Frio region and other areas can elucidate fundamental aspects of spatial and temporal site fidelity knowledge of Bryde's whales in southeastern Brazil.

Critically endangered western gray whales migrate to the eastern North Pacific.

Western North Pacific gray whales (WGWs), once considered extinct, are critically endangered with unknown migratory routes and reproductive areas. We attached satellite-monitored tags to seven WGWs on their primary feeding ground off Sakhalin Island, Russia, three of which subsequently migrated to regions occupied by non-endangered eastern gray whales (EGWs). A female with the longest-lasting tag visited all three major EGW reproductive areas off Baja California, Mexico, before returning to Sakhalin Island the following spring. Her 22 511 km round-trip is the longest documented mammal migration and strongly suggests that some presumed WGWs are actually EGWs foraging in areas historically attributed to WGWs. The observed migration routes provide evidence of navigational skills across open water that break the near-shore north-south migratory paradigm of EGWs. Despite evidence of genetic differentiation, these tagging data indicate that the population identity of whales off Sakhalin Island needs further evaluation.

Sperm whale response to tag boat presence: biologically informed hidden state models quantify lost feeding opportunities

Animal‐attached sensors provide invaluable data to describe behavior of cryptic species, such as cetaceans, and are increasingly used to assess anthropogenic disturbance effects. Tag deployment and handling may itself alter the behavior of study animals and there is a need to assess if and when behavior recovers to an undisturbed level. Not all behavioral changes have fitness consequences, and our goal is to derive metrics that can be linked to fitness implications, such as time and energy allocation to different functional behaviors. Here we detail an approach that incorporates biological knowledge and multiple streams of tag‐recorded data in a hidden state‐switching model to estimate time series of functional behavioral st ates for 12 sperm whales off Norway. Foraging, recovery and resting states were specified in the hidden state model by state‐dependent likelihood structures. Comparison of hidden state models revealed a parsimonious set of input time series, and supported the inclusion of a less informed ‘silent active' state. There was a high agreement between state estimates and expert classifications. We then used the estimated states in time series models to test three hypotheses for behavioral change during suction‐cup tag deployment procedures: change in behavioral states, change in prey capture attempts and locomotion cost, given behavioral state. Sperm whales spent 34% less time at the sea surface and 60% more time in non‐foraging silent active state in the presence of the tag boat (“tagging period” 0.1–2.8 h) than during post‐tagging baseline period (1.8–20.8 h). No comparable pre‐tagging baseline data were available. Nevertheless, time‐decaying models of tagging effects were not retained in model selection, indicating a short‐term effect that ceased immediately after the tagging period. We did not find changes in energetic proxies, given behavioral state, however changes in functional state budget indicate costs in terms of lost feeding opportunities and recovery time at surface. These results are useful to quantitatively identify data periods that should not be considered baseline behavior within tag recordings. This functional state approach proves effective to quantify disturbance in terms of time and energy allocation that is based upon general principles that can be applied to other species and biologging applications.

Whale killers: Prevalence and ecological implications of killer whale predation on humpback whale calves off Western Australia

AbstractReports of killer whales (Orcinus orca) preying on large whales have been relatively rare, and the ecological significance of these attacks is controversial. Here we report on numerous observations of killer whales preying on neonate humpback whales (Megaptera novaeangliae) off Western Australia (WA) based on reports we compiled and our own observations. Attacking killer whales included at least 19 individuals from three stable social groupings in a highly connected local population; 22 separate attacks with known outcomes resulted in at least 14 (64%) kills of humpback calves. We satellite‐tagged an adult female killer whale and followed her group on the water for 20.3 h over six separate days. During that time, they attacked eight humpback calves, and from the seven known outcomes, at least three calves (43%) were killed. Overall, our observations suggest that humpback calves are a predictable, plentiful, and readily taken prey source for killer whales and scavenging sharks offWAfor at least 5 mo/yr. Humpback “escorts” vigorously assisted mothers in protecting their calves from attacking killer whales (and a white shark,Carcharodon carcharias). This expands the purported role of escorts in humpback whale social interactions, although it is not clear how this behavior is adaptive for the escorts.

Humpback whales off Namibia: occurrence, seasonality, and a regional comparison of photographic catalogs and scarring

Abstract Humpback whales (Megaptera novaeangliae) from a breeding ground off Gabon (0–4°S) and a migratory corridor/feeding ground on the west coast of South Africa (WSA; 33°S) differ genetically and in catch histories. Interpretation of the population structure is hampered by the lack of data from the intervening 3,500 km of coastline or to the north of Gabon. Here we collate all relevant nongenetic data on humpback whales from Namibia (∼23°S) from 2005 to 2012 and compare these with corresponding data from Gabon (2000–2006) and WSA (1983–2008). Data from Namibia include photographic catalogs of dorsal fin and tail fluke images, seasonal presence, and a photographic assessment of scarring and wounds from cookiecutter sharks (Isistius sp.). No confirmed photographic identification matches could be made between Namibia and Gabon and only 2 potential matches were made between Namibia and WSA from dorsal fins. Humpback whales in Namibia show a bimodal seasonality in occurrence, with a primary peak in austral...

Spatio-temporal distribution of sperm whales (Physeter macrocephalus) off Kaikoura, New Zealand, in relation to bathymetric features

Using a shore-based station we monitored the position of sperm whales (Physeter macrocephalus) within the Kaikoura submarine canyon from 2010 to 2012. We tracked sperm whales using a theodolite station for a total of 290 days. We extracted the distance from the nearest coast, the depth and the bathymetric slope using ArcGIS 10.1. We estimated the seasonal spatial distribution of sperm whales using general additive models. The distribution varied significantly between seasons; individuals were found in deeper water and further offshore in the spring than in winter. This study improved our understanding of the variability of sperm whale distribution patterns off Kaikoura. We determined that the distribution was linked to the bathymetric features and we hypothesized that whales adapted their use of the submarine canyon in relation to food aggregation. We would encourage further studies to evaluate the sperm whale relationship with oceanographic variables off Kaikoura.

Sociality of sperm whale off Ischia Island (Tyrrhenian Sea, Italy)

ABSTRACT The sperm whale (Physeter macrocephalus) is one of the eight species of cetaceans routinely encountered in the Mediterranean Sea; however, information on the social organization of sperm whales living in the basin remains scarce. The social behaviour of sperm whales within female units, and groups of males are reported, made over an 11‐year period (2002–2012) in waters around the islands of Ischia and Ventotene (Tyrrhenian Sea, Italy), an area characterized by the presence of a submarine canyon system and a coastal marine protected area (‘Regno di Nettuno’ MPA). Different types of aggregations were identified, consisting of social units and two arrangements of males (bachelor groups and clusters). Close clustering at the surface was recorded both for social units and bachelor groups, with evidence for long‐term relationships between females (as expected from other studies) and, surprisingly, also among some immature males. Such long‐term associations between individuals in bachelor groups may allow immature males to benefit in several ways, including optimizing feeding efficiency. Copyright © 2014 John Wiley & Sons, Ltd.

Correcting Positional Errors in Shore-Based Theodolite Measurements of Animals at Sea

Determining the position of animals at sea can be particularly difficult and yet, accurate range and position of animals at sea are essential to answer a wide range of biological questions. Shore-based theodolite techniques have been used in a number of studies to examine marine mammal movement patterns and habitat use, offering reliable position measurements. In this study we explored the accuracy of theodolite measurements by comparing positional information of the same objects using two independent techniques: a shore-based theodolite station and an onboard GPS over a range of 25 km from the shore-based station. The technique was developed to study the habitat use of sperm whales (Physeter macrocephalus) off Kaikoura, New Zealand. We observed that the position accuracy fell rapidly with an increase in range from the shore-based station. Results showed that the horizontal angle was accurately determined, but this was not the case for the vertical angle. We calibrated the position of objects at sea with a regression-based correction to fit the difference in distance between simultaneously recorded theodolite fixes and GPS positions. This approach revealed the necessity to calibrate theodolite measurements with objects at sea of known position.

Migration timing and distance from shore of southbound eastern Pacific gray whales (Eschrichtius robustus) off Ensenada, Baja California, Mexico

AbstractEastern Pacific gray whales were monitored off Ensenada, Mexico, during the southbound migration. The objectives were to determine southbound migration timing and width of the migration corridor during three seasons (2003–2006). Migration timing was determined by fitting a generalized additive model to the shore counts for each season and estimating the 10, 50, and 90 percentiles of the fitted curves. To estimate abundance from shore‐based counts, a probability density function for the shore based distances was estimated by a product of a gamma distribution fit to the boat survey distance data for 2006/2007 and a half‐normal detection function using combined data of the three seasons. The parameters of the gamma distribution were corrected to account for less boat survey effort carried out 20–40 km than 0–20 km from shore. The onset of the migration off Ensenada was in late December/early January and ended around 13 February. The median date was 23–26 January for the first and third season and a week early for the second season. Boat surveys indicated a wide (20 km) migration corridor but most gray whales traveled within 9.9 km from shore. The estimated total number of whales during watch hours was 2,298 (95%CI= 1,536–4,447).

Movements of gray whales between the western and eastern North Pacific

ESR Endangered Species Research Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsSpecials ESR 18:193-199 (2012) - DOI: https://doi.org/10.3354/esr00447 FEATURE ARTICLE Movements of gray whales between the western and eastern North Pacific David W. Weller1,*, Amber Klimek2, Amanda L. Bradford3, John Calambokidis2, Aimee R. Lang1, Brian Gisborne4, Alexander M. Burdin5, Wendy Szaniszlo6, Jorge Urbán7, Alejandro Gómez-Gallardo Unzueta 7, Steven Swartz8, Robert L. Brownell Jr.1 1Protected Resources Division, Southwest Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, 3333 North Torrey Pines Court, La Jolla, California 92037-1022, USA 2Cascadia Research Collective, Olympia, Washington 98501, USA 3Protected Species Division, Pacific Islands Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Honolulu, Hawaii 96814, USA 4Juan de Fuca Express, Victoria, British Columbia, Canada 5Kamchatka Branch of Pacific Institute of Geography, Far East Branch - Russian Academy of Sciences, Petropavlovsk, Kamchatka, Russia 6PO Box 486, Ucluelet, British Columbia, Canada 7Programa de Investigación de Mamíferos Marinos, Universidad Autónoma de Baja California Sur, La Paz, B.C.S., Mexico 8Cetacean Research Associates, Darnestown, Maryland 20874, USA *Email: dave.weller@noaa.gov ABSTRACT: The western North Pacific (WNP) population of gray whales Eschrichtius robustus is redlisted by the IUCN as Critically Endangered. As part of a long-term study on whales off Sakhalin Island, Russia, photo-catalog comparisons of gray whales in the western and eastern North Pacific (ENP) were undertaken to assess population mixing. These comparisons involved 2 approaches: (1) a systematic comparison of the WNP ‘Sakhalin Catalog’ to an ENP ‘Pacific Northwest Catalog’ that consisted of images from the northwest coast of North America and (2) a non-systematic comparison of the WNP ‘Sakhalin Catalog’ to an ENP ‘Laguna San Ignacio Catalog’ that consisted of images from central Baja California, Mexico. The Sakhalin to Pacific Northwest comparison consisted of 181 and 1064 whales, respectively, and resulted in 6 matches (3 males, 2 females, and 1 whale of unknown sex). All sightings of ‘Sakhalin whales’ in the Pacific Northwest occurred off southern Vancouver Island, British Columbia, Canada. The Sakhalin to Laguna San Ignacio comparison consisted of 181 and 2514 whales, respectively, and resulted in 4 matches (2 males and 2 females). As the Pacific Northwest and Laguna San Ignacio catalogs represent only a small fraction of the total estimated number of individuals in the ENP population (~19000), it is likely that more WNP/ENP exchange has occurred than was detected by these photo-catalog comparisons. Although these matches provide new records of movements between the WNP and ENP, recent observations of gray whales off Japan and China suggest that not all gray whales identified in the WNP share a common wintering ground. KEY WORDS: Gray whale · Pacific Ocean · Movement patterns · Conservation Full text in pdf format Information about this Feature Article NextCite this article as: Weller DW, Klimek A, Bradford AL, Calambokidis J and others (2012) Movements of gray whales between the western and eastern North Pacific. Endang Species Res 18:193-199. https://doi.org/10.3354/esr00447 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in ESR Vol. 18, No. 3. Online publication date: September 12, 2012 Print ISSN: 1863-5407; Online ISSN: 1613-4796 Copyright © 2012 Inter-Research.

Is it possible to go whale watching off the coast of Peru? A case study of humpback whales

Whale watching is the human activity of encountering cetaceans in their natural habitat for recreational and scientific purposes. Despite the high diversity of cetaceans in Peruvian waters, this activity has yet to be developed. Herein we present data regarding the distribution of humpback whales (Megaptera novaeangliae) off northern Peru, evaluating the possibility of extending whale watching activities in this area. Data were obtained from surveys conducted from an ecotourism boat. Humpbacks were distributed in shallow waters, usually in pairs or trios throughout the study period between late July and late September. The presence of whales off northern Peru is due to winter migration for breeding and calving purposes. A high probability of encountering humpbacks within the study area could encourage the development of a whale watching industry. As this stage in the life cycle of this species is very delicate, we suggest the adoption of the precautionary principle in the management of the activity in order to minimize the risk of negative impacts on humpback populations. Whale watching in northern Peru is feasible and could be considered an alternative to fishing.

Is it possible to go whale watching off the coast of Peru? A case study of humpback whales

Whale watching is the human activity of encountering cetaceans in their natural habitat for recreational and scientific purposes. Despite the high diversity of cetaceans in Peruvian waters, this activity has yet to be developed. Herein we present data regarding the distribution of humpback whales (Megaptera novaeangliae) off northern Peru, evaluating the possibility of extending whale watching activities in this area. Data were obtained from surveys conducted from an ecotourism boat. Humpbacks were distributed in shallow waters, usually in pairs or trios throughout the study period between late July and late September. The presence of whales off northern Peru is due to winter migration for breeding and calving purposes. A high probability of encountering humpbacks within the study area could encourage the development of a whale watching industry. As this stage in the life cycle of this species is very delicate, we suggest the adoption of the precautionary principle in the management of the activity in order to minimize the risk of negative impacts on humpback populations. Whale watching in northern Peru is feasible and could be considered an alternative to fishing.

Using directional frequency sonobouys to localize singing humpback whales.

For many years, the navy has been using directional frequency analysis and recording (DIFAR) sonobouys to record and track ships. DIFAR sonobouys compute the acoustic particle velocity for two bimodal perpendicular hydrophone elements which, with an omnidirectional hydrophone and magnetic compass, gives a directional bearing to the sound. The omnidirectional hydrophone is also used to record sounds. DIFAR can be more accurate for low‐frequency whale calls than time of arrival methods, and only requires the three co‐located elements, which can function autonomously without a ship. In this study, we used two moored DIFAR sonobouys over a period of 4 days to record and track multiple singing humpback whales (Megaptera novaeangliae) off of Kaena Point, Oahu, HI. The distance between the two sonobouys was 1100 m. The digital acoustic signal was recoded at the sonobouy to preserve full dynamic range before multiplexing, and was analyzed in the laboratory using custom MATLAB programs. DIFAR localizations were correlated with visual observations from both the vessel and a 950 elevation land‐based location. Relative locations of singing humpbacks and durations of song were recorded. In addition, source levels for singing whales were also calculated.

A description of sounds recorded from melon-headed whales (Peponocephala electra) off Hawai‘i

Between 2004 and 2006, large groups of melon-headed whales were recorded off the Big Island of Hawai'i. No other odontocete species were sighted in these groups. Recordings contained echolocation clicks, burst-pulse sounds, and whistles. Echolocation clicks typically contained energy beginning at 13 kHz and continued strongly to the frequency cutoff of the recording system, suggesting that the frequency content of the clicks continued well beyond 24 kHz. Burst-pulse sounds were typically short, with a mean duration of 586 ms with a mean inter-pulse interval of 2.47 ms. The distribution of numbers of pulses was skewed toward fewer pulses, with a mean of 46.7 pulses. Overall, whistles were relatively simple frequency-modulated downsweeps, upsweeps, and sinusoidal signals. Fundamental frequencies ranged from 890 Hz to 23.5 kHz. Most whistles had smooth contours, although frequency steps were observed. Whistles were generally short, with a mean duration of 586 ms. The acoustic characteristics of these whistles were similar to those in the only previously published descriptions of melon-headed whale vocalizations [Watkins et al. (1997). Caribbean J. Sci. 33, 34-40; Janik and Curran (2007). 17th Biennial Conference on the Biology of Marine Mammals, Capetown, South Africa] and were shown to be distinguishable from whistles of other odontocete species.