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Understanding species' critical habitat requirements is crucial for effective conservation and management. However, such information can be challenging to obtain, particularly for highly mobile, wide-ranging species such as cetaceans. In the absence of systematic surveys, alternative economically viable methods are needed, such as the use of data collected from platforms of opportunity, and modelling techniques to predict species distribution in un-surveyed areas. The present study used data collected by ecotourism and other vessels of opportunity to investigate important habitats of a small, poorly studied population of bottlenose dolphins in Port Phillip Bay, south-eastern Australia. Using 16 years of dolphin sighting location data, an ensemble habitat suitability model was built from which physical factors influencing dolphin distribution were identified. Results indicated that important habitats were those areas close to shipping channels and coastlines with these factors primarily influencing the variation in the likelihood of dolphin presence. The relatively good performance of the ensemble model suggests that simple presence-background data may be sufficient for predicting the species distribution where sighting data are limited. However, additional data from the center of Port Phillip Bay is required to further support this contention. Important habitat features identified in the study are likely to relate to favorable foraging conditions for dolphins as they are known to provide feeding, breeding, and spawning habitat for a diverse range of fish and cephalopod prey species. The results of the present study highlight the importance of affordable community-based data collection, such as ecotourism vessels, for obtaining information critical for effective management. [ABSTRACT FROM AUTHOR]

Cetaceans of the family Delphinidae are widely distributed throughout the global ocean, and it has been suggested that females exhibit philopatry. However, the duration of time that a maternal group of these highly mobile creatures spends inhabiting a particular region remains unknown. The objective of this study is to examine the genetic diversity of delphinids in the past and to shed light on the above question. In this study, we amplified and sequenced the mitochondrial DNA D-loop region from the skeletal remains of delphinids that were excavated from the Shomyoji Midden, a site situated on the western coast of Tokyo Bay and dating to 5000–3000 years before the present. We acquired prehistoric D-loop sequences of seven bottlenose dolphins, six Pacific white-sided dolphins, and a false killer whale. Notably, one or more haplotypes from the prehistoric individuals were detected in the geographically proximate modern conspecific populations across all three species. Whilst the genetic diversity of prehistoric and modern Pacific white-sided dolphin populations appears to be comparable, the modern bottlenose dolphin population demonstrates significantly lower genetic diversity when compared to its prehistoric counterpart in the vicinity of Tokyo Bay. The maternal groups of these species are speculated to have persisted in the same habitat for at least 4000 years. [ABSTRACT FROM AUTHOR]

A review of the prey of three amphiatlantic dolphin species, Tursiops truncatus, Stenella coeruleoalba and Delphinus delphis, is carried out. The main objective of this work is to review the feeding of these species in the Atlantic in order to assess the degrees of trophic competition and speciation pressure. A total of 103 fish families, 22 cephalopod families and 19 crustacean families have been counted, from which the species identified to the genus level only included seventy-one fish, twenty cephalopods and five crustaceans, and the total species identified included three-hundred-one fish, fifty cephalopods and twenty-six crustaceans. The most consumed prey were fish, followed by cephalopods and crustaceans. The exclusive prey consumed by each of the three dolphin species, as well as those shared by all or at least two of them, have also been counted. T. truncatus is the most general; however, the western Atlantic populations exhibit high dietary specialization compared to the eastern Atlantic populations, reflecting strong speciation pressure on both sides of the Atlantic. D. delphis and S. coeruleoalba, despite their amphiatlantism, have hardly been studied in the western Atlantic, except for a few references in the southern hemisphere, so the fundamental differences between the two species and their comparison with T. truncatus have been established with records from the eastern Atlantic. All three dolphin species have been observed to be expanding, especially D. delphis. This northward expansion and that of their prey is discussed. [ABSTRACT FROM AUTHOR]

Understanding species’ critical habitat requirements is crucial for effective conservation and management. However, such information can be challenging to obtain, particularly for highly mobile, wide-ranging species such as cetaceans. In the absence of systematic surveys, alternative economically viable methods are needed, such as the use of data collected from platforms of opportunity, and modelling techniques to predict species distribution in un-surveyed areas. The present study used data collected by ecotourism and other vessels of opportunity to investigate important habitats of a small, poorly studied population of bottlenose dolphins in Port Phillip Bay, south-eastern Australia. Using 16 years of dolphin sighting location data, an ensemble habitat suitability model was built from which physical factors influencing dolphin distribution were identified. Results indicated that important habitats were those areas close to shipping channels and coastlines with these factors primarily influencing the variation in the likelihood of dolphin presence. The relatively good performance of the ensemble model suggests that simple presence-background data may be sufficient for predicting the species distribution where sighting data are limited. However, additional data from the center of Port Phillip Bay is required to further support this contention. Important habitat features identified in the study are likely to relate to favorable foraging conditions for dolphins as they are known to provide feeding, breeding, and spawning habitat for a diverse range of fish and cephalopod prey species. The results of the present study highlight the importance of affordable community-based data collection, such as ecotourism vessels, for obtaining information critical for effective management.

A review of the prey of three amphiatlantic dolphin species, Tursiops truncatus, Stenella coeruleoalba and Delphinus delphis, is carried out. The main objective of this work is to review the feeding of these species in the Atlantic in order to assess the degrees of trophic competition and speciation pressure. A total of 103 fish families, 22 cephalopod families and 19 crustacean families have been counted, from which the species identified to the genus level only included seventy-one fish, twenty cephalopods and five crustaceans, and the total species identified included three-hundred-one fish, fifty cephalopods and twenty-six crustaceans. The most consumed prey were fish, followed by cephalopods and crustaceans. The exclusive prey consumed by each of the three dolphin species, as well as those shared by all or at least two of them, have also been counted. T. truncatus is the most general; however, the western Atlantic populations exhibit high dietary specialization compared to the eastern Atlantic populations, reflecting strong speciation pressure on both sides of the Atlantic. D. delphis and S. coeruleoalba, despite their amphiatlantism, have hardly been studied in the western Atlantic, except for a few references in the southern hemisphere, so the fundamental differences between the two species and their comparison with T. truncatus have been established with records from the eastern Atlantic. All three dolphin species have been observed to be expanding, especially D. delphis. This northward expansion and that of their prey is discussed.

Social behaviours can allow individuals to flexibly respond to environmental change, potentially buffering adverse effects. However, individuals may respond differently to the same environmental stimulus, complicating predictions for population-level response to environmental change. Here, we show that bottlenose dolphins (Tursiops truncatus) alter their social behaviour at yearly and monthly scales in response to a proxy for food availability (salmon abundance) but do not respond to variation in a proxy for climate (the North Atlantic Oscillation index). There was also individual variation in plasticity for gregariousness and connectedness to distant parts of the social network, although these traits showed limited repeatability. By contrast, individuals showed consistent differences in clustering with their immediate social environment at the yearly scale but no individual variation in plasticity for this trait at either timescale. These results indicate that social behaviour in free-ranging cetaceans can be highly resource dependent with individuals increasing their connectedness over short timescales but possibly reducing their wider range of connection at longer timescales. Some social traits showed more individual variation in plasticity or mean behaviour than others, highlighting how predictions for the responses of populations to environmental variation must consider the type of individual variation present in the population. [ABSTRACT FROM AUTHOR]

Bottlenose dolphins (Tursiops spp.) are found in waters around Australia, with T. truncatus typically occupying deeper, more oceanic habitat, while T. aduncus occur in shallower, coastal waters. Little is known about the colonization history of T. aduncus along the Western Australian coastline; however, it has been hypothesized that extant populations are the result of an expansion along the coastline originating from a source in the north of Australia. To investigate the history of coastal T. aduncus populations in the area, we generated a genomic SNP dataset using a double‐digest restriction‐site‐associated DNA (ddRAD) sequencing approach. The resulting dataset consisted of 103,201 biallelic SNPs for 112 individuals which were sampled from eleven coastal and two offshore sites between Shark Bay and Cygnet Bay, Western Australia. Our population genomic analyses showed a pattern consistent with the proposed source in the north with significant isolation by distance along the coastline, as well as a reduction in genomic diversity measures along the coastline with Shark Bay showing the most pronounced reduction. Our demographic analysis indicated that the expansion of T. aduncus along the coastline began around the last glacial maximum and progressed southwards with the Shark Bay population being founded only 13 kya. Our results are in line with coastal colonization histories inferred for Tursiops globally, highlighting the ability of delphinids to rapidly colonize novel coastal niches as habitat is released during glacial cycle‐related global sea level and temperature changes. [ABSTRACT FROM AUTHOR]

Biphonation, deterministic chaos, sidebands and subharmonics are four non-linear phenomena (NLP) that have been identified as common additions in the phonations of animals. NLP have been hypothesised to communicate urgency, caller identification, fitness and arousal/valence states for a variety of species but have yet to be studied in detail for bottlenose dolphins. For this study, the signature whistles of nine bottlenose dolphins residing at the US Navy Marine Mammal Program (MMP) were opportunistically recorded during routine periods of separation from conspecifics. NLP were found to be common additions onto the spectral structure of signature whistles, occurring in 53% of recorded whistles (340/642). Sidebands were the most common NLP type produced. Although less frequently emitted, biphonations were characterised by a significantly longer persistence than the other NLP types. Age had a negative correlation with overall NLP presence, and more specifically, sideband presence. Individual differences in NLP use existed between dolphins; however, all dolphins were recorded producing a minimum of two NLP types. We describe NLP prevalence in dolphin whistles in order to provide a useful baseline for continued research to further identify changes in NLP across behavioural and/or health conditions. [ABSTRACT FROM AUTHOR]

Recently diverged taxa are often characterized by high rates of hybridization, which can complicate phylogenetic reconstruction. For this reason, the phylogenetic relationships and evolutionary history of dolphins are still not very well resolved; the question of whether the genera Tursiops and Stenella are monophyletic is especially controversial. Here, we performed re-sequencing of six dolphin genomes and combined them with eight previously published dolphin SRA datasets and six whole-genome datasets to investigate the phylogenetic relationships of dolphins and test the monophyly hypothesis of Tursiops and Stenella. Phylogenetic reconstruction with the maximum likelihood and Bayesian methods of concatenated loci, as well as with coalescence analyses of sliding window trees, produced a concordant and well-supported tree. Our studies support the non-monophyletic status of Tursiops and Stenella because the species referred these genera do not form exclusive monophyletic clades. This suggests that the current taxonomy of both genera might not reflect their evolutionary history and may underestimate their diversity. A four-taxon D-statistic (ABBA-BABA) test, five-taxon DFOIL test, and tree-based PhyloNet analyses all showed extensive gene flow across dolphin species, which could explain the instability in resolving phylogenetic relationship of oceanic dolphins with different and limited markers. This study could be a good case to demonstrate how genomic data can reveal complex speciation and phylogeny in rapidly radiating animal groups. [ABSTRACT FROM AUTHOR]

Aspergillosis remains difficult to diagnose in animals. Laboratory-based assays are far less developed than those for human medicine, and only few studies have been completed to validate their utility in routine veterinary diagnostics. To overcome the current limitations, veterinarians and researchers have to propose alternative methods including extrapolating from human diagnostic tools and using innovative technology. In the present overview, two specific examples were complementarily addressed in penguins and dolphins to illustrate how is challenging the diagnosis of aspergillosis in animals. Specific focus will be made on the novel application of simple testing in blood based on serological assays or protein electrophoresis and on the new information garnered from metabolomics/proteomics to discover potential new biomarkers. In conclusion, while the diagnostic approach of aspergillosis in veterinary medicine cannot be directly taken from options developed for human medicine, it can certainly serve as inspiration.

Some species exhibit behavioral plasticity by altering their aggressive behavior based on their opponent. Atlantic spotted dolphins (Stenella frontalis) and bottlenose dolphins (Tursiops truncatus) are two sympatric species resident to the northern Bahamas. We examined whether groups of adult male spotted dolphins demonstrated behavioral plasticity during two different types of aggressive interactions. We described and compared the types of aggressive behaviors used during intraspecific aggression and interspecific aggression with bottlenose dolphins. Between the years 1991-2004, twenty-two aggressive encounters (11 intraspecific (spotted only), 11 interspecific (spotted vs. bottlenose)) were behaviorally analyzed. Twenty-three specific aggressive Behavioral Events, further grouped into three Behavioral Types, were examined throughout these encounters. Similarities and differences in the use of the Behavioral Types occurred during intra- and interspecific aggression. Groups of male Atlantic spotted dolphins altered their behavior during aggressive encounters with male bottlenose dolphins. Spotted dolphins increased their use of the Pursuit Behavioral Type and did not use the Display Behavioral Type significantly more than the Contact Behavioral Type during interspecific aggression. The increased use of a more overt and energy intensive Behavioral Type, Pursuit, suggests that Atlantic spotted dolphins altered their behavior during aggressive encounters with bottlenose dolphins to compensate during fights with a larger species and/or to effectively communicate with a different species.

Aim: In the marine environment, where there are few physical boundaries to gene flow, there is often nevertheless intraspecific diversity with consequences for effective conservation and management. Here, we compare two closely related dolphin species with a shared distribution in the Indian Ocean (IO) to better understand the biogeographic drivers of their population structure. Location: Global oceans and seas with a focus on the Indian Ocean Taxon: Tursiops sp. and Delphinus sp. Methods: Bayesian, ordination, assignment, statistical and phylogenetic analyses to assess phylogeography, connectivity and population structure using microsatellite and mitochondrial DNA genetic markers. Results: Both Tursiops sp. and Delphinus sp. showed population structure across the western IO and, in each case, populations in the Arabian Sea (off India, Pakistan and Oman) were most differentiated. Comparisons with other populations worldwide revealed independent lineages in this geographic region for both genera. For T. aduncus, (for which multiple sites within the IO could be compared), Bayesian modelling best supported a scenario of expansion southwards following a bottleneck event resulting in differentiation between the northern and western IO. For Delphinus, the same pattern is even more pronounced. Populations in the Arabian Sea region of the north‐western IO show genetic isolation for each of the two genera, consistent with other studies of cetacean species in this region. Main conclusions: We propose that changes in the intensity of the southwest monsoon during the climate cycles of the Pleistocene could have affected regional patterns of productivity and represent an important biogeographic driver promoting the observed patterns of differentiation and population dynamics seen in our focal species. Patterns of population genetic structure are consistent with phenotypic differences, suggesting an influence from distinct habitats and resources, and emphasising the need for effective conservation measures in this geographic region. [ABSTRACT FROM AUTHOR]

Acoustical geographic variation is common in widely distributed species and it is already described for several taxa, at various scales. In cetaceans, intraspecific variation in acoustic repertoires has been linked to ecological factors, geographical barriers, and social processes. For the common bottlenose dolphin (Tursiops truncatus), studies on acoustic variability are scarce, focus on a single signal type—whistles and on the influence of environmental variables. Here, we analyze the acoustic emissions of nine bottlenose dolphin populations across the Atlantic Ocean and the Mediterranean Sea, and identify common signal types and acoustic variants to assess repertoires' (dis)similarity. Overall, these dolphins present a rich acoustic repertoire, with 24 distinct signal sub-types including: whistles, burst-pulsed sounds, brays and bangs. Acoustic divergence was observed only in social signals, suggesting the relevance of cultural transmission in geographic variation. The repertoire dissimilarity values were remarkably low (from 0.08 to 0.4) and do not reflect the geographic distances among populations. Our findings suggest that acoustic ecology may play an important role in the occurrence of intraspecific variability, as proposed by the 'environmental adaptation hypothesis'. Further work may clarify the boundaries between neighboring populations, and shed light into vocal learning and cultural transmission in bottlenose dolphin societies. [ABSTRACT FROM AUTHOR]

Globally, the exploitation of marine mammals has shifted from hunting to viewing over the last few decades. While refraining from actively killing animals may have a positive effect on marine mammal populations, whale and dolphin watching can induce changes such as displacement from preferred habitat and disruption of foraging that may also have severe fitness costs. Under some circumstances, this non-lethal disturbance may affect populations in a manner similar to directed mortality. Here, we focus on inshore dolphin populations that are known to show short-term behavioral responses to boat approaches. Long-term fitness effects have only been clearly identified in a small number of these populations, and all share certain characteristics, i.e., closed, small and food-limited. This raises the question of importance of context when considering the long-term effects of disturbance, since many dolphin populations may be open, large, and/or free from resource restriction. We explored the effect of disturbance based on the characteristics of populations using the population consequences of disturbance (PCoD) framework. PCoD was developed to link short-term changes in individual behavior and physiology to presumed long-term effects on population dynamics. To ensure our scenarios were biologically plausible, they reflected the ecological context of four well-studied populations of dolphins, Doubtful Sound, New Zealand, Sarasota Bay, United States, Durban Bay, South Africa, and Jervis Bay, Australia, in terms of their size, closure, and food resources. We found that the characteristics of the populations being disturbed are important with regards to the level of disturbance that could be tolerated. Closed populations were most sensitive, while large, open populations with no food limitation appeared to be able to withstand a higher probability of disturbance. This implies that population characteristics should be accounted for when determining the suitability of whale and dolphin watching operations in a given area.

Social connectivity is important for measuring the fitness of common bottlenose dolphins (Tursiops truncatus). While interactions in fission‐fusion societies vary between individuals, studies show that repeated interactions enhance reproduction and foraging success. Injuries that potentially remove an individual from its association network may disrupt these interactions. Using data from the long‐term resident dolphin community in Sarasota Bay, Florida, we investigated how anthropogenic injuries affect the dolphins' social associations by examining the differences before and after injury to individuals. We examined group size, strength, eigenvector centrality, clustering coefficient, and number of triangles and analyzed whether the animal's sex, age class, type of injury, or human intervention affected these values. We found that while group size did not change, injured dolphins had fewer preferred associates (HWI > 0.14) and were found in more fluid groups immediately after injury, but started returning to normal association levels after 2 years. This initial decrease in connectivity was not related to the age, sex, type of injury, or intervention. Despite the fluidity in individual associations, the strongest bonds remained stable, those between mothers and calves and those between male alliance partners. These findings provide some of the first information relating injuries and social networks for animals. [ABSTRACT FROM AUTHOR]

A distinct ulcerative dermatitis known as "freshwater skin disease" is an emerging clinical and pathological presentation in coastal cetaceans worldwide. In Australia, two remarkably similar mortality events enabled the creation of a case definition based on pathology and environmental factors. The first affected a community of endemic Tursiops australis in the Gippsland Lakes, Victoria, while the second occurred among T. aduncus resident in the Swan-Canning River system, Western Australia. The common features of both events were (1) an abrupt and marked decrease in salinity (from > 30ppt to < 5ppt) due to rainfall in the catchments, with hypo-salinity persisting weeks to months, and (2) dermatitis characterized grossly by patchy skin pallor that progressed to variable circular or targetoid, often raised, and centrally ulcerated lesions covering up to 70% of the body surface. The affected skin was often colonized by a variety of fungal, bacterial and algal species that imparted variable yellow, green or orange discoloration. Histologic lesions consisted of epidermal hydropic change leading to vesiculation and erosion; alternately, or in addition, the formation of intra-epithelial pustules resulting in ulceration and hypodermal necrosis. Thus, the environmental factors and characteristic pathologic lesions, are necessary components of the case definition for freshwater skin disease. [ABSTRACT FROM AUTHOR]

Bottlenose dolphins make many different sounds that have been recorded and described by researchers for over 60 years. This species, Tursiops truncatus, is arguably the most studied marine mammal. They have the ability to hear and produce sounds over a range of at least 150 kilohertz (kHz). Although the human hearing is limited in bandwidth to less than 20 kHz, dolphin sounds have historically been described as humans perceive them (e.g. whistles, squeals, buzzes, barks, quacks, pops, etc.). Often the same names have been used for different sounds and different names have been used for sounds that are apparently the same. In this review, we try and summarize the dolphin sound literature and provide standardized spectrograms where possible. Our goal is to provide a foundation for future research to build upon by providing a tool for identifying whether a sound has been described before. Novel sound types can then be recognized. Also, we encourage future studies that show when dolphins perceive two sound types as different. Detailed reports linking sound and behaviour are also essential. Only then can we have a complete idea of the dolphin repertoire and begin to understand how they use sound for communication. [ABSTRACT FROM AUTHOR]

The turbulent waters off ocean beaches provide habitat for large marine fauna, including dolphins, sharks, rays, turtles and game fish. Although, historically, these assemblages have proven difficult to quantify, we used a new drone-based approach to assess spatial and temporal variation in assemblages of large marine fauna off four exposed beaches in New South Wales, Australia. In total, 4388 individual large marine animals were identified from 216 drone flights. The most common taxa, bottlenose dolphins (Tursiops spp.) and Australian cownose rays (Rhinoptera neglecta), occurred in 25.5 and 19.9% of flights respectively. White (Carcharodon carcharias), bull (Carcharhinus leucas) and other whaler (Carcharhinus spp.) sharks were observed in <1% of flights. There was significant variation in the structure of assemblages of large fauna among beaches, with those adjacent to riverine estuaries having greater richness and abundance of wildlife. Overall, drone surveys were successful in documenting the spatio-temporal dynamics of an impressive suite of large marine fauna. We contend that emerging drone technology can make a valuable contribution to the ecological information required to ensure the long-term sustainability of sandy-beach ecosystems and associated marine wildlife. We used aerial drone surveys to quantify assemblages of large marine fauna off exposed beaches. Bottlenose dolphins and Australian cownose rays were the most observed animals. White, bull and other whaler sharks were observed in <1% of flights. Overall, drone surveys were successful in quantifying the spatio-temporal dynamics of an impressive suite of large marine fauna. [ABSTRACT FROM AUTHOR]

Urinalysis is a rapid, simple, inexpensive, and reliable test that documents urine abnormalities reflecting various types of renal, hormonal, or metabolic diseases. Urinalysis could assist proper monitoring of the health of dolphins under human care; however, normal baseline values for dolphin urinalysis have not been reported, to our knowledge. We sampled urine from 193 common bottlenose dolphins (Tursiops truncatus), living under human care in 24 Caribbean dolphinariums, by voluntary free-catch and analyzed the urine for chemical and microscopic variables using multi-agent dry reagent chemistry dipstick test strips, dedicated pH reagent strips, and unstained sediment slides. Most urine was clear, pale yellow to dark yellow, and had a fishy odor. Dipstick glucose, bilirubin, ketones, and nitrites were negative in all dolphins. The urine pH was acidic ( x ¯ ± SD; 5.88 ± 0.58) and specific gravity (SG) was 1.035 ± 0.008. Most animals had 0–2 red blood cells and white blood cells per 40× field, and were negative for proteins. On microscopic sediment, 42.7% of samples had few-to-many squamous epithelial cells; hyaline and epithelial casts were observed only rarely. Crystals were observed in 36.6% of the samples; most were calcium oxalate dihydrate (48.2%) and amorphous urates (42.4%). The values obtained in our study can be used as a reference for health monitoring of dolphins in dolphinariums, and to monitor renal conditions and function in dolphins being rehabilitated or under human care. [ABSTRACT FROM AUTHOR]

The article discusses how the franciscana dolphin is an endemic species from the southwestern Atlantic Ocean. A total of 20 franciscana dolphins stranded or entangled in fishing nets in Uruguay were dissected to evaluate possible variation among animals, five 1-wk-old calves and 15 adults. It notes that the nasal complex and it diverticulum, which is the most variable portion, operates as air reservoirs and acoustic reflectors concentrating the sound energy into the melon

The article discusses how the fins of humpback dolphins are small and positioned atop a slowly rising dorsal ridge. It notes that the attachment of satellite-linked radio-transmitters to small cetaceans has become a common technique for studying diving behavior, habitat selection, and movements. It adds that the dorsal fin of S. plumbea exhibited a higher degree of branching of the vessels compared to T. aduncus, with the vascular orientation running perpendicular to the cut surface of the fin.

Cetacean integument serves many functional roles, including contribution to whole body buoyancy. The blubber of the integument of different cetacean species contains varying concentrations of triacylglycerols (TAG) and wax esters (WE); generally, these lipid classes have different densities. Integument can also experience a wide range of temperatures during a dive, so its density may change with depth. The goals of this study were to measure integument density and isolated blubber lipid density in three deep‐diving odontocete species (n = 3–4)—short‐finned pilot whales (Globicephala macrorhynchus), pygmy sperm whales (Kogia breviceps), and Gervais' beaked whales (Mesoplodon europeaus)—at different temperatures (6°C–35°C), and to relate these densities to lipid content and composition. Kogia and Mesoplodon integument and isolated lipids had high WE content (78.7–99.5 wt%) and were less dense (by 1.7%–9.3%) than those of Globicephala, which were composed predominately of TAG. Generally, densities increased as temperature decreased. Changes in integument densities mirrored those of isolated lipid densities, suggesting that blubber lipids are largely responsible for the buoyant properties of cetacean integument. These data demonstrate that the contribution of the integument to whole body density depends on lipid class and temperature, and therefore may provide useful, species‐specific correction factors for diving energetics models. [ABSTRACT FROM AUTHOR]

The article discusses how long-finned pilot whales inhabit the cold temperate waters of the North Atlantic and the Southern Hemisphere, comprising two antitropical populations that are geographically isolated. It notes that the sample totaled 93 adult specimens, 69 from the southern South Atlantic Ocean and 24 from the North Atlantic. A principal component analysis (PCA) was performed to determine positions of the specimens along major multivariate axes.

Irrawaddy dolphins (Orcaella brevirostris) are threatened, little‐known cetaceans primarily jeopardized by fishing gear entanglement. Information regarding life history, foraging ecology, and movement are crucial to determine management units and conservation regions. This is the first analysis of the ontogenetic changes in diet and habitat of Irrawaddy dolphins from the Gulf of Thailand and the Andaman Sea using stable isotopes from skin and teeth. Results suggest limited age and sex structure indicated by weak ontogenetic and sexual variability in δ15N and δ13C in teeth. Significant variation in δ13C and δ15N values were observed between three Gulf regions and the Andaman Sea, indicating distinct regional groups. Isotope mixing models run on soft tissues from the eastern Gulf revealed a diet based primarily on fishes and secondarily on crustaceans, suggesting overlap with fishery targets. Conservation strategies that focus on reducing regional competition with humans and bycatch mortality are proposed. Fishing gear improvements and monitoring of fishing operations are a potential immediate response to reduce anthropogenic impact. [ABSTRACT FROM AUTHOR]

Fecal samples collected from free-ranging Atlantic bottlenose dolphins (BDs) in the Indian River Lagoon of Florida were processed for viral discovery using a next-generation sequencing (NGS) approach. A 693-bp contig identified in the NGS data was nearly identical to the partial L1 gene sequence of a papillomavirus (PV) previously found in a penile papilloma in a killer whale (Orcinus orca). Based on this partial bottlenose dolphin papillomavirus (BDPV) sequence, a nested inverse PCR and primer-walking strategy was employed to generate the complete genome sequence. The full BDPV genome consisted of 7299 bp and displayed a typical PV genome organization. The BDPV E6 protein contained a PDZ-binding motif, which has been shown to be involved in carcinogenic transformation involving high-risk genital human PVs. Screening of 12 individual fecal samples using a specific endpoint PCR assay revealed that the feces from a single female BD displaying a genital papilloma was positive for the BDPV. Genetic analysis indicated that this BDPV (Tursiops truncatus papillomavirus 8; TtPV8) is a new type of Dyopipapillomavirus 1, previously sequenced from an isolate obtained from a penile papilloma in a harbor porpoise (Phocoena phocoena). Although only a partial L1 sequence has been determined for a PV detected in a killer whale genital papilloma, our finding of a nearly identical sequence in an Atlantic BD may indicate that members of this viral species are capable of host jumping. Future work is needed to determine if this virus is a high-risk PV that is capable of inducing carcinogenic transformation and whether it poses a significant health risk to wild delphinid populations. [ABSTRACT FROM AUTHOR]

Understanding the drivers underlying fluctuations in the size of animal populations is central to ecology, conservation biology, and wildlife management. Reliable estimates of survival probabilities are key to population viability assessments, and patterns of variation in survival can help inferring the causal factors behind detected changes in population size. We investigated whether variation in age‐ and sex‐specific survival probabilities could help explain the increasing trend in population size detected in a small, discrete population of bottlenose dolphins Tursiops truncatus off the east coast of Scotland. To estimate annual survival probabilities, we applied capture–recapture models to photoidentification data collected from 1989 to 2015. We used robust design models accounting for temporary emigration to estimate juvenile and adult survival, multistate models to estimate sex‐specific survival, and age models to estimate calf survival. We found strong support for an increase in juvenile/adult annual survival from 93.1% to 96.0% over the study period, most likely caused by a change in juvenile survival. Examination of sex‐specific variation showed weaker support for this trend being a result of increasing female survival, which was overall higher than for males and animals of unknown sex. Calf survival was lower in the first than second year; a bias in estimating third‐year survival will likely exist in similar studies. There was some support first‐born calf survival being lower than for calves born subsequently. Coastal marine mammal populations are subject to the impacts of environmental change, increasing anthropogenic disturbance and the effects of management measures. Survival estimates are essential to improve our understanding of population dynamics and help predict how future pressures may impact populations, but obtaining robust information on the life history of long‐lived species is challenging. Our study illustrates how knowledge of survival can be increased by applying a robust analytical framework to photoidentification data. We applied capture–recapture models to photoidentification data to investigate whether variation in age‐ and sex‐specific survival probabilities could help explain a detected increasing trend in abundance in a small, discrete bottlenose dolphin population. We found strong support for an increase in juvenile/adult annual survival from 93.1% to 96.0% from 1989 to 2015, most likely caused by a change in juvenile survival. There was weaker support for this trend being a result of increasing female survival, which was overall higher than for males and animals of unknown sex. Calf survival was lower in the first than second year. [ABSTRACT FROM AUTHOR]

In recent decades, a number of studies have examined whether various non-human animals understand their partner's role in cooperative situations. Yet the relatively tolerant timing requirements of these tasks make it theoretically possible for animals to succeed by using simple behavioural strategies rather than by jointly intended coordination. Here we investigated whether bottlenose dolphins could understand a cooperative partner's role by testing whether they could learn a button-pressing task requiring precise behavioural synchronization. Specifically, members of cooperative dyads were required to swim across a lagoon and each press their own underwater button simultaneously (within a 1 s time window), whether sent together or with a delay between partners of 1-20 s. We found that dolphins were able to work together with extreme precision even when they had to wait for their partner, and that their coordination improved over the course of the study, with the time between button presses in the latter trials averaging 370 ms. These findings show that bottlenose dolphins can learn to understand their partner's role in a cooperative situation, and suggest that the behavioural synchronization evident in wild dolphins' synchronous movement and coordinated alliance displays may be a generalized cognitive ability that can also be used to solve novel cooperative tasks. [ABSTRACT FROM AUTHOR]

Dolphin cognitive abilities have been examined by establishing a concept-oriented cue, the innovate discriminative stimulus (SD), wherein an individual is required to perform something new or different upon each stimulus given. Although a number of facilities have trained this behavior with a wide range of species, neither the training nor the level of creativity in response to this cue has been researched systematically. Moreover, differing criteria exist for whether novel or different behaviors should be defined as innovative as evidenced by the research to date. Ultimately, our goal is to establish a research and training protocol for using the innovate SD to assess the creative abilities in nonhuman species. We compared innovate training methodologies used with dolphins specifically, although a number of other species have been trained on this behavior based on anecdotal reports. Our literature review, including discussions with trainers, indicated that a number of potential pitfalls occur when training this cognitive task (e.g., avoid shaping a chained behavioral response). This methodological review provides both a clear definition of the criteria accepted for innovative behavior and a suggested approach for training and testing this concept in dolphins. Finally, the more unambiguously that we understand innovative behavior in a controlled setting, such as under stimulus control, the more we will be able to gain from studies of spontaneous behavior and other examples of behavioral innovation observed in the wild. [ABSTRACT FROM AUTHOR]

The objective of this study was to test the potential influence of short-term changes in water quality on the frequency of sightings of common dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida. The study was based on two data sources: (1) Land/Ocean Biogeochemical Observatories (LOBOs) that provided real-time monitoring of multiple water quality and weather parameters, and (2) standardized methods for identifying and counting individual dolphins using photo-identification techniques. Water quality parameters included salinity, water color (chromophoric dissolved organic matter), conductivity, dissolved oxygen concentration, oxygen saturation, chlorophyll, nitrate and phosphate concentrations, temperature, and turbidity. Weather was assessed using data for air temperature, barometric pressure, humidity, light, and wind speed and direction. Variables were measured continuously over a one-year period and analyzed as the mean for each parameter the hour before, during, and after each dolphin sighting period. Short-term variations in sightings within 0.5 km of the LOBO were measured using previously established photo-identification techniques on a weekly basis. In multivariable regression analyses, statistically significant inverse associations were found between air temperature and the frequency of dolphin sightings for all three time periods. The results demonstrate the feasibility of integrating variation in weather and water chemistry data with dolphin movements as potential indicators of ecosystem quality and climate change. [ABSTRACT FROM AUTHOR]

Variation in dorsal fin morphology was assessed in five common bottlenose dolphin populations from the Southeast Pacific. We hypothesized that habitat specialization between coastal and offshore ecotypes would lead to differences in dorsal fin morphology. Photographs and direct measurements of dorsal fins were used to calculate three indexes: height / length base ( h / b), width at half height / length base (a / b), and overhang of the dorsal fin tip/ length base (falcateness) (s/ b). The sample included 163 individuals (129 coastal and 34 offshore) from Ecuador, 60 individuals (nine coastal and 51 offshore) from Peru, and 25 individuals of an inshore community occurring in north-central Chile (Pod-R). Ontogenetic variation was found in coastal dolphins from Ecuador, where sex and age classes were best represented. A statistically significant difference was found in the a / b index between coastal specimens from Ecuador and Peru and among the three offshore groups. When offshore and Pod-R data were pooled and compared with data from coastal specimens from Ecuador and Peru, a significant difference was found in the s/ b index. Overall, dorsal fins of offshore dolphins are relatively higher than fins of coastal individuals. However, the most consistent difference between ecotypes was the strong falcateness ( high s/ b) in offshore forms versus a more triangular shape ( low s/ b) in coastal forms. We propose that dorsal fin falcateness is a reliable criterion to visually distinguish between bottlenose dolphin ecotypes in this region. Proper identification in the field greatly facilitates research and helps focus management needs of the different bottlenose dolphin populations. [ABSTRACT FROM AUTHOR]

Little is known about the population ecology of the recently described bottlenose dolphin species Tursiops australis. The classification of this species is still under debate, but this putative species is thought to be comprised of small and genetically distinct populations (including sub-populations under increasing anthropogenic threats) and is likely endemic to coastal southern Australia. Mitochondrial DNA (mtDNA) control region sequences and microsatellite loci were used to assess genetic variation and hierarchical population structure of coastal T. cf. australis across a range of spatial scales and environmental discontinuities between southern Western Australia (WA) and central South Australia (SA). Overall, genetic diversity was similar to that typically found for bottlenose dolphins, although very low mtDNA diversity was found in Gulf St. Vincent (GSV) dolphins. We found historical genetic subdivision and likely differences in colonisation between GSV and Spencer Gulf, outer- and inner-gulf locations, and SA/WA and previously identified Victorian/Tasmanian populations. A hierarchical metapopulation structure was revealed along southern Australia, with at least six genetic populations occurring between Esperance, WA and southern Tasmania. In addition, fine-scale genetic subdivision was observed within each SA/WA population. In general, contemporary migration was limited throughout southern Australia, but an important gene flow pathway was identified eastward along the Great Australian Bight. Management strategies that promote gene flow among populations should be implemented to assist with the maintenance of the inferred metapopulation structure. Further research into the population ecology of this species is needed to facilitate well-informed management decisions. [ABSTRACT FROM AUTHOR]

The welfare of a range of terrestrial animals can now be objectively estimated thanks to the wellestablished, but still expanding, field of welfare science. Despite continuing difficulties regarding definitions, it is generally agreed that welfare is assessed most accurately using multiple "animal-based measures"-that is, those evaluating aspects of the animal itself such as its behaviour. In addition, scientists combining behavioural, physiological, and cognitive animal-based indicators of welfare have found this approach is superior to using one-dimensional measures. But can the same approaches be used for marine mammals, and would assessments of their welfare have the same relevance in captivity as in wild environments? There is no reason why not, and we review the past decades of marine mammal research relevant to welfare, as well as the more recent advances in the field where this topic is starting to be addressed directly. We then use the example of bottlenose dolphins (Tursiops truncatus) to examine what the measures within an all-encompassing (i.e., "comprehensive") welfare assessment might look like. Looking to the future, we suggest directions for developing assessments for captive animals and explore how protocols might differ in wild settings. In conclusion, we find that the first steps are being made towards objectively assessing marine mammal welfare in captivity-through application of terrestrial animal approaches as well as through novel paradigms. Regarding bottlenose dolphins, several welfare measures have been proposed and should now be further validated and applied. It is hoped that this review will encourage continued research in marine mammal welfare assessment given the demonstrated initial achievements of bottlenose dolphin welfare studies and the potential for application to many different captive and wild contexts. [ABSTRACT FROM AUTHOR]

Long-term studies often rely on natural markings for individual identification across time. The primary method for identification in small cetaceans relies on dorsal fin shape, scars, and other natural markings. However, dorsal fin markings can vary substantially over time and the dorsal fin can become unrecognizable after an encounter with a boat or shark. Although dorsal fins have the advantage in that they always break the water surface when the cetacean breathes, other physical features, such as body scars and pigmentation patterns can supplement. The goal of this study was to explore the use of dorso-lateral pigment patterns to identify wild bottlenose dolphins. We employed photographic pigment matching tests to determine if pigmentation patterns showed (1) longitudinal consistency and (2) bilateral symmetry using a 30 yr photographic database of bottlenose dolphins ( Tursiops aduncus). We compared experienced dolphin researchers and inexperienced undergraduate student subjects in their ability to accurately match images. Both experienced and inexperienced subjects correctly matched dolphin individuals at a rate significantly above chance, even though they only had 10 s to make the match. These results demonstrate that pigment patterns can be used to reliably identify individual wild bottlenose dolphins, and likely other small cetacean species at other sites. [ABSTRACT FROM AUTHOR]

Knowledge of an animal's home range is a crucial component in making informed management decisions. However, many home range studies are limited by study area size, and therefore may underestimate the size of the home range. In many cases, individuals have been shown to travel outside of the study area and utilize a larger area than estimated by the study design. In this study, data collected by multiple research groups studying bottlenose dolphins on the east coast of Florida were combined to determine how home range estimates increased with increasing study area size. Home range analyses utilized photo-identification data collected from 6 study areas throughout the St Johns River (SJR; Jacksonville, FL, USA) and adjacent waterways, extending a total of 253 km to the southern end of Mosquito Lagoon in the Indian River Lagoon Estuarine System. Univariate kernel density estimates (KDEs) were computed for individuals with 10 or more sightings (n = 20). Kernels were calculated for the primary study area (SJR) first, then additional kernels were calculated by combining the SJR and the next adjacent waterway; this continued in an additive fashion until all study areas were included. The 95% and 50% KDEs calculated for the SJR alone ranged from 21 to 35 km and 4 to 19 km, respectively. The 95% and 50% KDEs calculated for all combined study areas ranged from 116 to 217 km and 9 to 70 km, respectively. This study illustrates the degree to which home range may be underestimated by the use of limited study areas and demonstrates the benefits of conducting collaborative science. [ABSTRACT FROM AUTHOR]

1. Assessments of demographic parameters are essential to understand the dynamics of wild populations, and for their efficient conservation and management. Here, sex-specific abundance, apparent survival and temporary emigration of southern Australian bottlenose dolphins (Tursiops cf. australis) in Coffin Bay (CB), South Australia, is investigated. 2. Results are based on capture-recapture modelling of photo-identification data and molecular analyses of biopsy samples collected during boat-based surveys between September 2013 and October 2015 in the inner and outer areas of CB. 3. The total super-population of dolphins (including calves) using the entire study area (263 km²) was estimated with POPAN models at 306 (95% CI: 291-323), which included 71 (68-73) marked females and 57 (55-60) marked males. 4. Seasonal estimates of abundance for the inner area of CB (123 km²)) obtained with Pollock's Closed Robust Design models remained relatively constant over the two years (marked females: 52-60, marked males: 46-52, and total: 193-209). 5. The high density of dolphins inhabiting the inner area (seasonal range: 1.57-1.70 individuals km-2), high apparent survival rates estimated for both sexes (females: 0.99; 95% CI: 0.96-1.0; males: 0.95; 0.82-0.99), and low temporary emigration rates (0.02; 95% CI: 0.01-0.11) indicate that the inner area of CB offers highly favourable habitat for these dolphins. 6. High biological productivity and low predation risk may promote these demographic patterns in the inner area of CB. 7. This study provides a robust baseline of sex-specific population demographics of southern Australian bottlenose dolphins with important implications for future research and their management and conservation in South Australia. [ABSTRACT FROM AUTHOR]

Due to their worldwide distribution and occupancy of different types of environments, bottlenose dolphins display considerable morphological variation. Despite limited understanding about the taxonomic identity of such forms and connectivity among them at global scale, coastal (or inshore) and offshore (or oceanic) ecotypes have been widely recognized in several ocean regions. In the Southwest Atlantic Ocean ( SWA), however, there are scarce records of bottlenose dolphins differing in external morphology according to habitat preferences that resemble the coastal-offshore pattern observed elsewhere. The main aim of this study was to analyze the genetic variability, and test for population structure between coastal ( n = 127) and offshore ( n = 45) bottlenose dolphins sampled in the SWA to assess whether their external morphological distinction is consistent with genetic differentiation. We used a combination of mt DNA control region sequences and microsatellite genotypes to infer population structure and levels of genetic diversity. Our results from both molecular marker types were congruent and revealed strong levels of structuring (microsatellites FST = 0.385, p < .001; mt DNA FST = 0.183, p < .001; Φ ST = 0.385, p < .001) and much lower genetic diversity in the coastal than the offshore ecotype, supporting patterns found in previous studies elsewhere. Despite the opportunity for gene flow in potential 'contact zones', we found minimal current and historical connectivity between ecotypes, suggesting they are following discrete evolutionary trajectories. Based on our molecular findings, which seem to be consistent with morphological differentiations recently described for bottlenose dolphins in our study area, we recommend recognizing the offshore bottlenose dolphin ecotype as an additional Evolutionarily Significant Unit ( ESU) in the SWA. Implications of these results for the conservation of bottlenose dolphins in SWA are also discussed. [ABSTRACT FROM AUTHOR]

In fission-fusion societies, group size and composition change dynamically, reflecting social preferences and pressures. Most notably during reproduction, intersexual group dynamics reflect a balance between female choice for optimal mates and male competition for mating access. In systems where males and females remain in their natal area for life (bisexual philopatry), females can reduce the risk of incest by avoiding mating or associating with male kin. Shark Bay bottlenose dolphins ( Tursiops aduncus) live in fission-fusion societies that enable them to exercise age, sex, and kin association biases. To determine how the balance between female choice and male competition is achieved, we examined adult female association with juvenile and adult males, including sons during female receptive periods, using 30 years of longitudinal data. Adult females demonstrated an increase in adult male association just prior to known conceptions, while juvenile male association consistently remained low. A decline in male association post-conception suggests that one or both sexes detect pregnancy early on. When we examined female association with juvenile and adult sons, a distinct pattern emerged. Adult females preferentially associated with sons compared to non-sons of the same age class post-weaning. Strikingly, females rarely associated with their adult sons when cycling. Our results suggest that (1) adult males either out-compete juvenile males in gaining access to fertile females or females prefer adult to juvenile males and (2) females mitigate the risk of close inbreeding by reducing association with sons when cycling. Significance statement: No study has investigated behavioral strategies for reducing close inbreeding in bisexually philopatric, fluid mammal societies outside of humans. Using over 30 years of longitudinal data, we document how association dynamics change with female reproductive state. Post-weaning, mothers and sons associate, but almost never during conceptive periods. Adult male-female association is frequent during estrous, with a sharp decline after conception. Our study provides evidence for long-term kin recognition and detection of both estrous and early pregnancy among wild bottlenose dolphins. These findings have implications for the evolution of bisexual philopatry, fission-fusion dynamics, and infanticide-or lack thereof-in mammals. [ABSTRACT FROM AUTHOR]

The first assessment of cetacean density and abundance by linear transect survey was conducted in 2016 and 2017 in the shallowest coastal area of the Ukrainian sector of the north-western Black Sea, in the Dzharylgach Gulf and the northern Karkinit Gulf, total area up to 259 km2. Three cetacean species were found present in the area in summer and the harbour porpoise was the most abundant species with the abundance of at least a few hundred animals (estimated as 175 individuals in the Dzharylgach Gulf), whereas the common dolphins (59) and bottlenose dolphins (31) were present in lesser numbers. Common and bottlenose dolphins showed the clearest patterns of habitat preferences, being restricted respectively to the Dzharylgach and the northern Karkinit Gulf; an unusual trait is the preference of the shallowest habitat by common dolphins. Recorded density of harbour porpoises in the Dzharylgach Gulf is among the highest in the whole Black Sea. Thus, the studied area may be an important summer habitat for cetaceans. [ABSTRACT FROM AUTHOR]

Sex differences in adult behaviour are well documented, but less is known about the ontogeny of these differences. In mammals, the transition to independence, from infancy to the juvenile period, is when these sex differences are likely to become prominent. Here, we examined sex differences in behavioural development among calf and juvenile bottlenose dolphins, Tursiops aduncus , from 2 years preweaning to 2 years postweaning and whether these differences were consistent, or not, with three nonmutually exclusive hypotheses regarding the function of the juvenile period: the social skills, protection/safety and energy allocation hypothesis. All hypotheses received some support, but strikingly so for females. First, sex differences in the nature and quality of juvenile social bonds appear to foreshadow adult association patterns. Juveniles had a greater proportion of same-sex associates than calves. Second, although neither sex increased their number of associates from infancy to juvenility, a pattern that might mitigate predation risk, avoidance between juveniles and adult males suggests that both sexes reduce the likelihood of conspecific aggression. This pattern was more marked for juvenile females. Third, females, but not males, increased foraging rates from late infancy to the early juvenile period, even surpassing typical adult female foraging rates. This is likely related to the future energetic demands of maternal investment and skill development required for specialized foraging tactics, which are female biased in this population. This study provides a first step towards understanding the transition into independence for cetaceans, insight into how sex differences develop and a glimpse into the function of the juvenile period. [ABSTRACT FROM AUTHOR]

Objective: Anal glands have been identified in a variety of terrestrial and aquatic mammalian species, but there are few accounts describing their presence in cetaceans. To our knowledge, this report describes the first documented case of a pre-anal gland abscess in an Atlantic bottlenose dolphin (Tursiops truncatus)., Animal: A 9-year-old male bottlenose dolphin (T truncatus) part of the US Navy Marine Mammal Program in San Diego Bay, California., Clinical Presentation, Progression, and Procedures: The patient presented for a 3-day history of lethargy, failure to perform voluntary behaviors, and an elevated respiratory rate. Complete blood count and serum biochemistry results showed an inflammatory hemogram. Physical examination revealed a 4-cm circular swelling at the right pre-anal gland pore. The swelling was warm and erythematous, with multifocal pinpoint ulcerations. An abscess of the pre-anal gland was diagnosed using cytology, culture, and ultrasound., Treatment and Outcome: Treatment included systemic oral antibiotic and antifungal therapy, along with daily lavage and warm compress of the gland. Treatment was successful, and the abscess resolved., Clinical Relevance: This case provides insight into a previously unreported disease process in bottlenose dolphins and encourages veterinarians to evaluate the pre-anal gland during routine physical examinations and complete further work-up if swelling or clinical signs associated with this region are present.