Pseudorca Crassidens Research Articles

Insights sobre um encalhe em massa de falsas orcas (Pseudorca Crassidens Owen, 1846)

False killer whales (FKWs; Pseudorca crassidens) are found in deep waters of temperate and tropical oceans worldwide. This species is considered near threatened and global populations’ trends are unknown although there is evidence of decline of various populations. The mass stranding of cetaceans remains an intriguing event and often the cause(s) are unclear or poorly investigated. In Brazil, cetacean mass strandings have been recorded yet they have not been investigated. In this study, we aimed to report the epidemiologic features of a mass stranding event involving 30 live FKWs occurred in northeastern Brazil in 2013. Releasing attempts and posterior monitoring data indicated successful outcome for 24 of 30 FKWs. Postmortem pathologic investigations confirmed live-stranding stress response and intestinal (Bolbosoma sp.) and otic (Stenurus sp.) endoparasitism. Toxicologic analyzes detected high concentrations of total mercury in liver correlating with liver damage, as indicated by elevated transaminases. In this mass stranding, key factors were early notification, organizational and operational framework, trained and sufficient personnel, resources and equipment, government support, and strategy and decision making. These results underscore the benefits of a rapid marine mammal network response, the importance of integrative multidisciplinary investigations, and set baseline information for mass strandings of cetaceans in Brazil.

Discriminating and classifying odontocete echolocation clicks in the Hawaiian Islands using machine learning methods.

Passive acoustic monitoring (PAM) has proven a powerful tool for the study of marine mammals, allowing for documentation of biologically relevant factors such as movement patterns or animal behaviors while remaining largely non-invasive and cost effective. From 2008–2019, a set of PAM recordings covering the frequency band of most toothed whale (odontocete) echolocation clicks were collected at sites off the islands of Hawaiʻi, Kauaʻi, and Pearl and Hermes Reef. However, due to the size of this dataset and the complexity of species-level acoustic classification, multi-year, multi-species analyses had not yet been completed. This study shows how a machine learning toolkit can effectively mitigate this problem by detecting and classifying echolocation clicks using a combination of unsupervised clustering methods and human-mediated analyses. Using these methods, it was possible to distill ten unique echolocation click ‘types’ attributable to regional odontocetes at the genus or species level. In one case, auxiliary sightings and recordings were used to attribute a new click type to the rough-toothed dolphin, Steno bredanensis. Types defined by clustering were then used as input classes in a neural-network based classifier, which was trained, tested, and evaluated on 5-minute binned data segments. Network precision was variable, with lower precision occurring most notably for false killer whales, Pseudorca crassidens, across all sites (35–76%). However, accuracy and recall were high (>96% and >75%, respectively) in all cases except for one type of short-finned pilot whale, Globicephala macrorhynchus, call class at Kauaʻi and Pearl and Hermes Reef (recall >66%). These results emphasize the utility of machine learning in analysis of large PAM datasets. The classifier and timeseries developed here will facilitate further analyses of spatiotemporal patterns of included toothed whales. Broader application of these methods may improve the efficiency of global multi-species PAM data processing for echolocation clicks, which is needed as these datasets continue to grow.

Insights into acoustic behavior of false killer whales

The Hawaiian Archipelago is home to three distinct populations of false killer whales (Pseudorca crassidens), including one currently listed as endangered. These delphinids are known to interact with fishing gear, leading to whale mortality or injury. Hence, it is critical to assess the abundance of these populations typically achieved through visual-based sighting surveys. However, these surveys are complicated by a number of biases and uncertainties specific to this species. Passive acoustics could aid in monitoring of their population status, but the knowledge is limited about the patterns in their acoustic repertoire and behavior, which hinders our ability to derive reliable acoustics-based abundance estimates. Here, we discuss insights into the acoustic behaviour of false killer whales in the wild, gained by simultaneous tracking of both narrowband whistles and broadband echolocation clicks from towed hydrophone arrays. The results indicate a diverse acoustic behaviour between different subgroups within the same encounter, where 23.8% of subgroups (N total = 408) only echolocate, 18.9% only whistle, and 57.3% emit both types of vocalizations. Such increased understanding of false killer whale vocal behavior can contribute information from passive acoustic data for management and conservation purposes.

The Potential Distribution and Maternal Lineage of Two Cetaceans Species (Grampus griseus and Pseudorca crassidens) in the Subfamily Globicephalinae from the Thai Andaman Sea and the Gulf of Thailand

Although the existence of two cetacean species in and around Thai Seas from within the subfamily Globicephalinae, Risso’s dolphin Grampus griseus G. Cuvier, 1812, and false killer whale Pseudorca crassidens Owen, 1846, has been known for decades, current knowledge on the abundance, genetic diversity, and conservation status of these marine mammals is limited as these are rare oceanic species for Thailand’s territorial waters. Frozen skin tissue samples taken from six cetaceans (four Risso’s dolphins: two false killer whales) stranded along Thai coastlines were investigated. We aimed to identify the maternal lineage and connection of our samples throughout their distribution range. Accordingly, we analyzed the dataset of 110 and 50 mtDNA control region sequences of Risso’s dolphins and false killer whales, respectively. This dataset was retrieved from the online database of the National Center for Biotechnology Information (NCBI) and included six mtDNA sequences obtained from Thai Seas. Two unique haplotypes of Risso’s dolphins were found in the Thai Andaman Sea, whereas one haplotype identified as being from the Gulf of Thailand is a common haplotype shared with other regions of the Pacific Ocean. Two haplotypes were found for false killer whales from the Thai Andaman Sea, and these were also in common with other regions of the Indo Pacific Ocean. While shared haplotypes with other regions may imply inheritance from the same female ancestor, we speculate that distinct populations with unique genetic structures also exist in Thai Seas. Beneficially, our results could be used to monitor alterations of haplotypes or to assess the maternal genetic diversity of designated species in the future to establish baseline information for Thai Seas and adjacent waters.

The origins of the killer whale ecomorph

The killer whale (Orcinus orca) and false killer whale (Pseudorca crassidens) are the only extant cetaceans that hunt other marine mammals, with pods of the former routinely preying on baleen whales >10 m in length and the latter being known to take other delphinids.1-3 Fossil evidence for the origins of this feeding behavior is wanting, although molecular phylogenies indicate that it evolved independently in the two lineages.4 We describe a new extinct representative of the killer whale ecomorph, Rododelphis stamatiadisi, based on a partial skeleton from the Pleistocene of Rhodes (Greece). Five otoliths of the bathypelagic blue whiting Micromesistius poutassou are associated with the holotype, providing unexpected evidence of its last meal. The evolutionary relationships of R. stamatiadisi and the convergent evolution of killer whale-like features were explored through a broad-ranging phylogenetic analysis that recovered R. stamatiadisi as the closest relative of P. crassidens and O. orca as the only living representative of a once diverse clade. Within the clade of Orca and kin, key features implicated in extant killer whale feeding, such as body size, tooth size, and tooth count, evolved in a stepwise manner. The tooth wear in Rododelphis and an extinct species of Orcinus (O. citoniensis) are consistent with a fish-based diet, supporting an exaptative Pleistocene origin for marine mammal hunting in both lineages. If correct, predation by the ancestors of Pseudorca and Orca did not play a significant role in the evolution of baleen whale gigantism. VIDEO ABSTRACT.

Dolphin Distribution and Habitat Suitability in North Western Australia: Applications and Implications of a Broad-Scale, Non-targeted Dataset

Understanding species’ distribution patterns and the environmental and ecological interactions that drive them is fundamental for biodiversity conservation. Data deficiency exists in areas that are difficult to access, or where resources are limited. We use a broad-scale, non-targeted dataset to describe dolphin distribution and habitat suitability in remote north Western Australia, where there is a paucity of data to adequately inform species management. From 1,169 opportunistic dolphin sightings obtained from 10 dugong aerial surveys conducted over a four-year period, there were 661 Indo-Pacific bottlenose dolphin (Tursiops aduncus), 191 Australian humpback dolphin (Sousa sahulensis), nine Australian snubfin dolphin (Orcaella heinsohni), 16 Stenella sp., one killer whale (Orcinus orca), one false killer whale (Pseudorca crassidens), and 290 unidentified dolphin species sightings. Maximum Entropy (MaxEnt) habitat suitability models identified shallow intertidal areas around mainland coast, islands and shoals as important areas for humpback dolphins. In contrast, bottlenose dolphins are more likely to occur further offshore and at greater depths, suggesting niche partitioning between these two sympatric species. Bottlenose dolphin response to sea surface temperature is markedly different between seasons (positive in May; negative in October) and probably influenced by the Leeuwin Current, a prominent oceanographic feature. Our findings support broad marine spatial planning, impact assessment and the design of future surveys, which would benefit from the collection of high-resolution digital images for species identification verification. A substantial proportion of data were removed due to uncertainties resulting from non-targeted observations and this is likely to have reduced model performance. We highlight the importance of considering climatic and seasonal fluctuations in interpreting distribution patterns and species interactions in assuming habitat suitability.

Marine resource recovery in Southern Thailand during COVID-19 and policy recommendations

COVID-19 and subsequent government health containment measures have slowed down economic activities worldwide, particularly tourism. With the number of foreign tourists entering Thailand during 2020 and 2021 greatly diminished, the number of tourists at marine and coastal attractions in Southern Thailand has declined as well. This study found evidence of a relationship between the decline of the number of tourists and marine resource recovery. This recovery appears in the form of cleaner beaches, clearer seawater and increased sighting of marine animals. Between 2020 and 2021, official reports found increased sighting of dugongs, dolphins, blacktip reef sharks, whale sharks, leopard sharks, sea turtles, green turtles, hawksbill turtles, and false killer whales at marine national parks in Southern Thailand. The study also found that, prior to the COVD-19 outbreak, the number of tourists at Patong Beach and Maya Bay exceeded their tourism carrying capacities. Finally, this study proposes eight policy measures related to tourism management for marine resource sustainability: conservation and recreation zoning, enforcing marine park closure, redesigning marine park entrance fee systems, ensuring adequate recreational facilities, stricter enforcement of the law, promoting alternative tourism sites, encouraging more inclusivity and participation in decision making processes, and enhancing public awareness.

Skull morphological variation in a British stranded population of false killer whale (Pseudorca crassidens): a three-dimensional geometric morphometric approach

The false killer whale (Pseudorca crassidens (Owen, 1846)) is a globally distributed delphinid that shows geographical differentiation in its skull morphology. We explored cranial morphological variation in a sample of 85 skulls belonging to a mixed sex population stranded in the Moray Firth, Scotland, in 1927. A three-dimensional digitizer (Microscribe 2GX) was used to record 37 anatomical landmarks on the cranium and 25 on the mandible to investigate size and shape variation and to explore sexual dimorphism using geometric morphometric. Males showed greater overall skull size than females, whereas no sexual dimorphism could be identified in cranial and mandibular shape. Allometric skull changes occurred in parallel for both males and females, supporting the lack of sexual shape dimorphism for this particular sample. Also, fluctuating asymmetry did not differ between crania of males and females. This study confirms the absence of sexual shape dimorphism and the presence of a sexual size dimorphism in this false killer whale population.

Tracking time differences of arrivals of multiple sound sources in the presence of clutter and missed detections.

Acoustic line transect surveys are often used in combination with visual methods to estimate the abundance of marine mammal populations. These surveys typically use towed linear hydrophone arrays and estimate the time differences of arrival (TDOAs) of the signal of interest between the pairs of hydrophones. The signal source TDOAs or bearings are then tracked through time to estimate the animal position, often manually. The process of estimating TDOAs from data and tracking them through time can be especially challenging in the presence of multiple acoustically active sources, missed detections, and clutter (false TDOAs). This study proposes a multi-target tracking method to automate TDOA tracking. The problem formulation is based on the Gaussian mixture probability hypothesis density filter and includes multiple sources, source appearance and disappearance, missed detections, and false alarms. It is shown that by using an extended measurement model and combining measurements from broadband echolocation clicks and narrowband whistles, more information can be extracted from the acoustic encounters. The method is demonstrated on false killer whale (Pseudorca crassidens) recordings from Hawaiian waters.

Patterns of depredation in the Hawai‘i deep‐set longline fishery informed by fishery and false killer whale behavior

AbstractFalse killer whales (Pseudorca crassidens) depredate bait and catch in the Hawai‘i‐based deep‐set longline fishery, and as a result, this species is hooked or entangled more than any other cetacean in this fishery. We analyzed data collected by fisheries observers and from satellite‐linked transmitters deployed on false killer whales to identify patterns of odontocete depredation that could help fishermen avoid overlap with whales. Odontocete depredation was observed on ˜6% of deep‐set hauls across the fleet from 2004 to 2018. Model outcomes from binomial GAMMs suggested coarse patterns, for example, higher rates of depredation in winter, at lower latitudes, and with higher fishing effort. However, explanatory power was low, and no covariates were identified that could be used in a predictive context. The best indicator of depredation was the occurrence of depredation on a previous set of the same vessel. We identified spatiotemporal scales of this repeat depredation to provide guidance to fishermen on how far to move or how long to wait to reduce the probability of repeated interactions. The risk of depredation decreased with both space and time from a previous occurrence, with the greatest benefits achieved by moving ˜400 km or waiting ˜9 d, which reduced the occurrence of depredation from 18% to 9% (a 50% reduction). Fishermen moved a median 46 km and waited 4.7 h following an observed depredation interaction, which our analysis suggests is unlikely to lead to large reductions in risk. Satellite‐tagged pelagic false killer whales moved up to 75 km in 4 h and 335 km in 24 h, suggesting that they can likely keep pace with longline vessels for at least four hours and likely longer. We recommend fishermen avoid areas of known depredation or bycatch by moving as far and as quickly as practical, especially within a day or two of the depredation or bycatch event. We also encourage captains to communicate depredation and bycatch occurrence to enable other vessels to similarly avoid high‐risk areas.

Rare records of the false killer whales (Pseudorca crassidens) in the Adriatic Sea

In spring 2021, four unusual encounters with a group of false killer whales were recorded in Kvarner Bay, Northern Adriatic Sea. A minimum of five individuals, including a calf, were observed and two photos were taken corroborating species identification. These are the first reported sightings of the species in the Adriatic Sea since the mid-twentieth century. In addition, another encounter was revealed that occurred at the end of the 2000s in the same location and should be added to the list of historic observations. These reports were obtained by chance and show the importance of citizen science in obtaining data on rare marine species. The information gathered goes towards a better understanding of the distribution of the species in the Mediterranean Sea.

Occurrence of false killer whales Pseudorca crassidens pod in the Ligurian Sea and review of Mediterranean records

Occurrence of false killer whales Pseudorca crassidens pod in the Ligurian Sea and review of Mediterranean records

Acoustic classification of false killer whales in the Hawaiian islands based on comprehensive vocal repertoire.

Use of underwater passive acoustic datasets for species-specific inference requires robust classification systems to identify encounters to species from characteristics of detected sounds. A suite of routines designed to efficiently detect cetacean sounds, extract features, and classify the detection to species is described using ship-based, visually verified detections of false killer whales (Pseudorca crassidens). The best-performing model included features from clicks, whistles, and burst pulses, which correctly classified 99.6% of events. This case study illustrates use of these tools to build classifiers for any group of cetacean species and assess classification confidence when visual confirmation is not available.

Towards non-invasive heart rate monitoring in free-ranging cetaceans: a unipolar suction cup tag measured the heart rate of trained Risso's dolphins.

Heart rate monitoring in free-ranging cetaceans to understand their behavioural ecology and diving physiology is challenging. Here, we developed a simple, non-invasive method to monitor the heart rate of cetaceans in the field using an electrocardiogram-measuring device and a single suction cup equipped with an electrode. The unipolar suction cup was placed on the left lateral body surface behind the pectoral fin of Risso's dolphins (Grampus griseus) and a false killer whale (Pseudorca crassidens) in captivity; their heart rate was successfully monitored. We observed large heart rate oscillations corresponding to respiration in the motionless whales during surfacing (a false killer whale, mean 47 bpm, range 20-75 bpm; Risso's dolphins, mean ± s.d. 61 ± 15 bpm, range 28-120 bpm, n = 4 individuals), which was consistent with the sinus arrhythmia pattern (eupneic tachycardia and apneic bradycardia) observed in other cetaceans. Immediately after respiration, the heart rate rapidly increased to approximately twice that observed prior to the breath. Heart rate then gradually decreased at around 20-50 s and remained relatively constant until the next breath. Furthermore, we successfully monitored the heart rate of a free-swimming Risso's dolphin. The all-in-one suction cup device is feasible for field use without restraining animals and is helpful in further understanding the diving physiology of free-ranging cetaceans. This article is part of the theme issue 'Measuring physiology in free-living animals (Part II)'.

Investigating the Diel Occurrence of Odontocetes around the Maui Nui Region Using Passive Acoustic Techniques1

The distribution of odontocetes on a daily scale is largely driven by bottom-up processes that in turn influence foraging opportunities. Environmental variables such as bathymetry may help indicate productive foraging regions and serve as useful tools when assessing dolphin spatial and temporal patterns. To begin to understand daily spatial patterns of different odontocete species relative to heterogeneous benthic habitat, passive acoustic monitoring was conducted near an understudied basin of the Hawaiian Islands, the Maui Nui region (Maui, Lāna‘i, Kaho‘olawe, Moloka‘i). Results showed that the acoustic activity of smaller species was stronger at night than day, particularly closer to shelf waters. In contrast, the acoustic activity of less common larger species tended not to follow a diel pattern, except at sites of a moderate proximity to shelf waters. These findings support previous research showing that smaller odontocetes, such as spinner dolphins (Stenella longirostris), track and feed upon the daily vertically migrating mesopelagic boundary community at night, while larger odontocetes, such as false killer whales (Pseudorca crassidens), may forage across most of the region during both the day and night. This information will help inform best management practices that account for interspecies variation in use of the Maui Nui basin.

Tourism informing conservation: The distribution of four dolphin species varies with calf presence and increases their vulnerability to vessel traffic in the four‐island region of Maui, Hawai‘i

Abstract We need reliable information about the spatial and temporal distribution of mobile species to effectively manage anthropogenic impacts to which they are exposed. Yet, we often cannot sustain dedicated annual surveys and data obtained from platforms of opportunity offer an alternative avenue to understand where these species spend time. Four odontocete species that occur in the four‐island region of Maui, Hawai'i, USA, are vulnerable to a range of human activities, but there is a lack of information regarding their distribution. We therefore do not know the extent of the risk these activities present for the conservation of these species (bottlenose dolphins, spinner dolphins, Pantropical spotted dolphins and false killer whales). We used a cross‐validated maximum entropy (MaxEnt) occupancy model to estimate the distribution of these four species in an area extensively observed from platforms of opportunity (PoP). We then determined in a similar fashion whether the calves of those species were more likely to be observed in particular areas and whether distribution changed with season. Maxent models relying on local environmental variables described dolphin observations well (AUC > 0.7). Their distribution differed for all species when calves were present, indicating that different environmental variables describe area use for schools with calves present. The number of sighting events of all species varied significantly with season. Bottlenose dolphins and false killer whales were more prevalent in winter, while spotted and spinner dolphins were more prevalent in summer. We show that an overlap in the distribution of dolphin schools with calves and vessel traffic in the region could result in collision and chronic stress risks. This suggests a need for specific regulations for mitigating anthropogenic influences, such as acoustic disturbance or chronic energetic disturbance from vessel traffic. This elevated risk associated with vessel traffic is likely of conservation concern in this region for the endangered population of false killer whales and for spinner dolphins.

The Challenges of Managing Depredation and Bycatch of Toothed Whales in Pelagic Longline Fisheries: Two U.S. Case Studies

Direct interactions with fisheries are broadly recognized as the leading conservation threat to small cetaceans. In open-ocean environments, one of the primary gear types implicated in these interactions is the pelagic longline. Unlike accidental entanglement in driftnets or deliberate entrapment by purse-seines, interactions between cetaceans and longlines are often driven by attraction of the animals to feed on bait or fish secured on the gear, a behavior known as depredation. Many small and medium-sized delphinid species have learned to exploit such opportunities, leading to economic costs to fisheries and a risk of mortality to the animals from either retaliation by fishermen or hooking or entanglement in fishing gear. Two pelagic longline fisheries in the United States experience depredation and bycatch by odontocete depredators: the Hawai‘i deep-set longline fishery, which is depredated primarily by false killer whales (Pseudorca crassidens), and the Atlantic pelagic longline fishery depredated primarily by short-finned pilot whales (Globicephala macrorhynchus). These fisheries are among the most intensively documented and managed pelagic longline fisheries in the world, with high levels of observer coverage, and bycatch mitigation measures required to reduce the mortality of seabirds, sea turtles and cetaceans. Both fisheries have active, multi-stakeholder “Take Reduction Teams,” enacted under the U.S. Marine Mammal Protection Act (MMPA), that are tasked to develop measures to reduce the bycatch of cetaceans below statutory reference points. Consequently, these two Teams represent model processes within which to address depredation and bycatch, having access to detailed, high-quality data on the nature and frequency of interactions with cetaceans, meaningful stakeholder involvement, resources to test potential solutions, and the institutional will to improve outcomes. We review how mitigation strategies have been considered, developed, and implemented by both Teams and provide a critical analysis of their effectiveness in addressing these problems. Notably, in the absence of straightforward avoidance or deterrence strategies, both Teams have developed gear and handling strategies that depend critically on comprehensive observer coverage. Lessons offered from these Teams, which have implemented consensus-driven management measures under a statutory framework, provide important insights to managers and scientists addressing other depredation problems.

Trace elements in subantarctic false killer whale (Pseudorca crassidens) tissues, including the skin as an offshore bioindicator.

On a global scale, cetaceans are recognized well indicators of marine ecosystem health. Trace elements accumulate in their bodies and potentially constitute a toxicological threat. Here, the concentrations of essential Se; unknown physiological elements Br, Rb, Cs, Ni, and Sr; and pollutants arsenic, Cd, Hg, and Ag were assessed in the skin of false killer whales (Pseudorca crassidens) stranded at Estrecho de Magallanes, South America, and next, tissue comparisons and relationships between elemental concentrations in the skin and internal tissues (liver, kidney, spleen, lung, skeletal muscle, and testis) were assessed. Results showed elemental concentration variations among tissues. Selenium concentration was found to be higher in the liver 398 (75) μg g-1 dry weight (DW) (standard deviation in parenthesis), followed by skin. Rubidium and Br concentrations were higher in testis 7.92 (0.42) and 99.1 (5.4) μg g-1 DW, respectively, and Cs in muscle 0.36 (0.12) μg g-1 DW, while Ni concentrations range (<0.05-0.91 μg g-1 DW) did not show differences among tissues. Cadmium and arsenic were found to be higher in kidneys, 71.2 (17.6) and 2.54 (1.77) μg g-1 DW, respectively, while Hg was highest in the liver 1068 (234) μg g-1 DW. Concerning inter-tissue relationships, a positive skin-to-kidney and skin-to-muscle correlations were observed for Cs concentrations, and also Hg showed positive skin-to-spleen, skin-to-kidney, and skin-to-testis correlations, which support its use as potential offshore marine biomonitor.

Bringing the right fishermen to the table: Indices of overlap between endangered false killer whales and nearshore fisheries in Hawaiʻi

Incidental bycatch in fisheries is a pressing conservation issue for marine mammal populations across the globe. However, the ability to detect and therefore mitigate this issue is challenging for several reasons. Fishermen are unlikely to voluntarily report bycatch due to fear of penalization or apathy towards it. While fisheries observer programs are sometimes in place to record bycatch, many fisheries have no observers. In Hawaiian waters there are no observer programs in nearshore fisheries, yet interactions with fisheries are likely the greatest threat to the endangered main Hawaiian Islands insular population of false killer whales (Pseudorca crassidens). We assess spatiotemporal overlap between false killer whales and nearshore fisheries in Hawai‘i to identify fisheries and regions where interactions are most likely to occur. Interactions with fisheries was cited as the greatest threat to this population's viability as a result of growing evidence over recent decades. We used false killer whale location data from 38 satellite tag deployments (2007–2018) and commercial fishery catch logs from a corresponding period to develop fishery overlap indices (FOIs) from a perspective that should reflect the experience of local fishermen. The area off Kona has the highest levels of fishing effort, but a low FOI, while high FOI values (up to several thousand times higher than Kona) were found off O‘ahu, Moloka‘i, Maui, Lāna‘i and the north end of Hawai‘i. Our findings provide direction for where efforts should be focused to effectively monitor and mitigate bycatch for this endangered population of false killer whales.

Cetacean sighting records in the New Caledonia Basin, Tasman Sea, New Zealand

ABSTRACT The distribution of marine mammal species in many areas remains poorly understood, especially as observations for some taxa are rare and large-scale surveys are time consuming and extremely costly. Here, we present 36 records of 7 cetacean species (Balaenoptera brydei, B. musculus subspp., Delphinus delphis, Globicephala sp., Grampus griseus, Physeter macrocephalus, Pseudorca crassidens) in the New Caledonia Basin, Tasman Sea, along with their associated biological and environmental data. Data were derived from a platform of opportunity during a seismic survey that ran between December 2015 and March 2016, inclusively. The two most frequently encountered species were sperm whales (Physeter macrocephalus, 13 sightings, 5 acoustic detections) and blue whales (Balaenoptera musculus subspp., 8 visual detections). All encountered species are known to occur in New Zealand waters at least occasionally, based on historical sightings and stranding records. However, data presented here are the first cetacean records for this specific area and demonstrate that seismic vessels can act as a platform of opportunity for studying cetacean distribution in poorly accessible areas. Such data will aid future research efforts including species distribution models on cetaceans in the South Pacific.