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Despite strong interest in how noise affects marine mammals, little is known for the most abundant and commonly exposed taxa. Social delphinids occur in groups of hundreds of individuals that travel quickly, change behaviour ephemerally and are not amenable to conventional tagging methods, posing challenges in quantifying noise impacts. We integrated drone-based photogrammetry, strategically placed acoustic recorders and broad-scale visual observations to provide complementary measurements of different aspects of behaviour for short- and long-beaked common dolphins. We measured behavioural responses during controlled exposure experiments (CEEs) of military mid-frequency (3-4 kHz) active sonar (MFAS) using simulated and actual Navy sonar sources. We used latent-state Bayesian models to evaluate response probability and persistence in exposure and post-exposure phases. Changes in subgroup movement and aggregation parameters were commonly detected during different phases of MFAS CEEs but not control CEEs. Responses were more evident in short-beaked common dolphins (n = 14 CEEs), and a direct relationship between response probability and received level was observed. Long-beaked common dolphins (n = 20) showed less consistent responses, although contextual differences may have limited which movement responses could be detected. These are the first experimental behavioural response data for these abundant dolphins to directly inform impact assessments for military sonars.

The common dolphin (Delphinus delphis) is a widely distributed species exhibiting extensive morphological diversity, with previous taxonomies recognizing multiple Delphinus species primarily based on relative beak length. We sequenced mitochondrial genomes of D. delphis morphotypes from multiple regions, calculated mitogenome nucleotide diversity (π = 0.00504), dated Delphinus mitogenome diversification to 1.27 mya, and conducted phylogenetic and population‐level analyses focusing on morphotype and geographic origin. We present the first Delphinus sequencing data from Senegal, at the edge of where long‐ and short‐beaked dolphins co‐occur in the Atlantic, but only recovering stranded dolphins with long or indeterminate beak lengths. While we detected little genetic structure across most of the North Atlantic, fixation indices demonstrate that Senegalese dolphins are distinct. Geography did not reliably predict phylogeny, with few monophyletic localities, but we do infer a monophyletic group of long‐beaked dolphins from California, Peru, and possibly China. However, neither Senegalese long‐beaked dolphins nor long‐beaked D. d. tropicalis are closely related to Pacific long‐beaked dolphins, providing no support for a worldwide long‐beaked clade (formerly D. capensis). Our findings reveal a distinctive Senegal Delphinus population and provide a foundation for global genomic analyses to further investigate the evolution of Delphinus morphotypes. [ABSTRACT FROM AUTHOR]

Despite strong interest in how noise affects marine mammals, little is known for the most abundant and commonly exposed taxa. Social delphinids occur in groups of hundreds of individuals that travel quickly, change behaviour ephemerally and are not amenable to conventional tagging methods, posing challenges in quantifying noise impacts. We integrated drone-based photogrammetry, strategically placed acoustic recorders and broad-scale visual observations to provide complementary measurements of different aspects of behaviour for short- and long-beaked common dolphins. We measured behavioural responses during controlled exposure experiments (CEEs) of military mid-frequency (3–4 kHz) active sonar (MFAS) using simulated and actual Navy sonar sources. We used latent-state Bayesian models to evaluate response probability and persistence in exposure and post-exposure phases. Changes in subgroup movement and aggregation parameters were commonly detected during different phases of MFAS CEEs but not control CEEs. Responses were more evident in short-beaked common dolphins (n = 14 CEEs), and a direct relationship between response probability and received level was observed. Long-beaked common dolphins (n = 20) showed less consistent responses, although contextual differences may have limited which movement responses could be detected. These are the first experimental behavioural response data for these abundant dolphins to directly inform impact assessments for military sonars.

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]

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.

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]

Understanding the effect of stage‐specific traits on species feeding habits can reveal how natural selection shapes life strategies. Amino acid (AA) nitrogen stable isotopes (δ15N) provide multiple proxies of habitat baseline values and diet that can improve our understanding of species feeding strategies relative to their animal metabolism. We evaluated the effect of body length as a proxy for life stage and sex on the feeding habits of the common dolphin Delphinus delphis delphis using δ13C and δ15N in bulk tissue and AAs δ15N from skin samples collected for almost two decades.For bulk δ13C and δ15N data, we used SIBER analysis to compare isotopic niches by sex and life stage. For AA δ15N data, we developed a hierarchical Bayesian model (HBM) to estimate indices of trophic status (Δ15N and trophic position). The model reflected the natural hierarchical structure of AA data by partitioning variability into three sources: between laboratory replicates, within dolphins and among dolphins.Estimates of Δ15N based on all trophic and source AAs were more precise for each dolphin, less variable among dolphins and on average 2.4‰ higher than indices based on single trophic (Glx) and source (Phe) AAs. Precision was further increased when information was shared among individuals through random effects or regression models. Estimates of trophic position showed similar patterns. Both Δ15N and δ15Nbulk isotopic niches showed no difference by sex, suggesting that males and females have similar feeding habits and may not segregate. However, lower Δ15N values for weaning calves and smaller juveniles discriminate them from adults, whereas δ15N bulk isotopic niches do not. A trophic discrimination factor (TDFTro‐Src) of 3.1‰ was required for reasonable estimates of trophic position for these dolphins.Together, the lack of δ15N differences between sexes, low variation between juveniles and adults and knowledge of common dolphins' social organization support intraspecific feeding cooperation as an important strategy to feed in the highly dynamic marine environment. Our study also presents an efficient way to analyse complex AA δ15N data using HBM to investigate foraging behaviour in long‐lived marine species difficult to study in the wild. [ABSTRACT FROM AUTHOR]

In 1815, the naturalist Constantine Samuel Rafinesque (1783–1840) previewed three new species of cetaceans – Delphinus dalippus, Physeter urganantus and Oxypterus mongitori – that he intended to describe from Sicily based on illustrations in Antonino Mongitore's published work Della Sicilia ricercata nelle cose più memorabili (1742–1743). Although formal descriptions of the three species were never published, Rafinesque's reference to Mongitore's illustrations made the names available by "indication". The names, nonetheless, fell into obscurity, most likely a result of contemporary taxonomists' lack of access to Mongitore's work. Rafinesque's names remain relevant to the history of cetacean taxonomy, although they are no longer applicable. Moreover, the animals associated with these names add to the historical record of whale strandings in the Mediterranean. For these reasons, we studied the illustrations Rafinesque indicated for his cetaceans and reviewed Mongitore's accompanying text, which together provide sufficient distinctive characters that two of the three animals can be confidently identified with modern species, namely the sperm whale, Physeter catodonLinnaeus, 1758, and the false killer whale, Pseudorca crassidens (Owen, 1846). Had Rafinesque's name D. dalippus been recognized for what it was, it would have had priority over P. crassidens as the earliest scientific name for the false killer whale. [ABSTRACT FROM AUTHOR]

Understanding how animals use the space in which they are distributed is important for guiding management decisions in conservation, especially where human disturbance can be spatially managed. Here we applied distribution modelling to examine common dolphin (Delphinus sp.) habitat use in the Hauraki Gulf (36°S, 175°E), New Zealand. Given the known importance of the area for foraging and nursing, we assessed which variables affect Delphinus occurrence based on generalised additive models (GAMs), and modelled probability of encounter. Behavioural information was included to assess habitat use by feeding and nursing groups and determine whether persistent hotspots for such activities could be identified and meaningfully used as a spatial management tool. Using data collected from dedicated boat surveys during 2010–2012, depth and sea surface temperature (SST) were frequently identified as important variables. Overall, seasonal predictive occurrence maps for the larger population resembled predictive maps of feeding groups more than nursery groups, suggesting prey availability has important implications for the distribution of Delphinus in this region. In this case, static spatial exclusions would not be the best management option as the core areas of use identified for these activities were large and shifted temporally. It appears that at the scale examined, most of the Hauraki Gulf is important for feeding and nursing rather than specific smaller regions being used for these functions. In cases where static management is not the optimal tool, as suggested here for a highly mobile species, a dynamic approach requires more than a boundary line on a map. [ABSTRACT FROM AUTHOR]

Eight species of Nearctic Eucosmini previously considered to be of uncertain generic assignment are reviewed and illustrated. The following new or revised combinations are proposed: Pelochrista aspidana (Walsingham), comb.n.; Eucosma delphinoides (Heinrich), comb.n.; Eucosma delphinus (Heinrich), comb.n.; Pelochrista excerptionana (Heinrich), comb.n.; Pelochrista fuscana (Kearfott), comb.n. and new synonymy with Pelochrista nandana (Kearfott); Eucosma sublapidana (Walsingham), comb.rev. Eucosma apriliana (Grote) and Eucosma gomonana Kearfott retain their former generic placements. Eucosma baggetti, a new species similar to Eucosma gomonana Kearfott, is described from southeastern United States. [ABSTRACT FROM AUTHOR]

Abstract Historical dwellings make up a significant fraction of the French building stock and require substantial retrofitting to reduce their energy consumption and improve their thermal comfort. In the city center of Cahors, France, the old medieval dwellings are considered as valuable cultural heritage and internal insulation is often the only insulation technique that can be used when the architectural value of the exterior façade is to be preserved. However, internal insulation may have an impact upon the hygrothermal performance of the wall, leading to lowered drying capacity, with possible interstitial condensation and mold growth. Hygrothermal models may be used to assess the risk of failure, but the accuracy of the results depends on how reliable the input data is, including external boundary conditions, which may vary significantly in dense medieval cities such as Cahors. In this study, a Geographical Information System model of Cahors is used to develop EnergyPlus models of individual dwellings. The boundary conditions output by these models are, in turn, used to model the hygrothermal performance of façades with different internal insulations, using the hygrothermal tool Delphin. The Delphin outputs are then analyzed with the VTT model, a mold growth assessment model. Results highlight a quantitative correlation between some urban morphology characteristics and the hygrothermal performance of refurbished walls, with some configurations raising the risk of damage patterns. We find that bio-based insulation presents a better hygrothermal performance than mineral wool in most of the configurations. [ABSTRACT FROM AUTHOR]

Whale tracking tags often penetrate semi-rigid blubber, with intramuscular sharp tips and toggling barbs under the subdermal sheath to reduce premature shedding. Tag sites can show persistent regional swellings or depressions. Fibroelastic blubber grips a tag, so if muscle shears relative to blubber during locomotion, the tag tip could cavitate the muscle within overall shearing distance. We modeled shearing of blubber relative to muscle, within the dorsalventral peduncular movement range of four common dolphin (Delphinus delphis) cadavers (mean length 186 cm). The net change in angle and hence tip distance moved was calculated with dorsal and ventral flexion, and compared between 1.5 mm diameter needles inserted into blubber only and through blubber into muscle. The greatest shearing value was 3.6 cm, and shearing was most pronounced in the areas ventral and caudal to the dorsal fin. Scaled dummy tags were also inserted and the animal cyclically flexed dorsally and ventrally for 18 h. Tag sites were dissected and cavities around the tag tips documented. If this shearing is comparable in large whales, depressions and regional swellings observed with intramuscular tracking tags are likely the result of tissue loss and repair, respectively. Placing tags para-sagittally anterior to the dorsal fin would cause the least trauma, but pain from such tags remains a concern. [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]

Phylogenetic relationships in the family Delphinidae have been widely debated. We examined 347 skulls of Tursiops, Stenella, Delphinus, Steno, Lagenodelphis, and Sousa in order to resolve the phylogenetic position of Australian species of Tursiops. Five Tursiops type specimens were included. Cranial morphology was described using 2-dimensional (2-D) and 3-dimensional geometric morphometrics (3- GM), counts and categorical data. Analyses showed a clear morphological separation of Tursiops, including type specimens, from other genera. The three Stenella species did not cluster together. Stenella attenuata clustered with Delphinus delphis, and Stenella coeruleoalba with Lagenodelphis hosei. Length and width of the skull and rostrum were important discriminators in both methods. For 3-D data, round vs. angular posterior skull shape distinguished some genera. Taxa that overlapped in the multivariate analyses had different mean tooth counts. Our study challenges genetic studies that identified Tursiops as polyphyletic, with T. aduncus closer to S. attenuata. [ABSTRACT FROM AUTHOR]

Many doubts still exist about which freshwater mussel Unio species inhabit Northwest Africa. While some authors refer to the presence of Unio delphinus in the Atlantic North African basins of Morocco, a recent International Union for Conservation of Nature (IUCN) assessment performed on Moroccan Unio species, recognised the existence of a distinct species, Unio foucauldianus, with a critically endangered conservation status. The present study delivered new genetic, morphological, and geographical distribution data on two Unio species (i.e . U. delphinus and U. foucauldianus) greatly increasing the almost non-existent data on these taxa. Bayesian phylogenetic analysis revealed two highly supported geographically concordant clades, which diverged by 3.2 ± 0.6 % (uncorrected p distance): the first distributed across Iberia and corresponding to U. delphinus, and the second distributed across Morocco, corresponding to U. foucauldianus. These results were corroborated by the analysis of ten newly developed microsatellite loci as well as shell morphometry. We suggest that the IUCN critically endangered conservation status of U. foucauldianus should be revised and probably down-listed since its actual distribution is much wider than previously described. Phylogenetic relationships with the other Unio species were resolved, showing that U. delphinus and U. foucauldianus fall inside the pictorum lineage. The estimated molecular rate reported herein (0.265 ± 0.06 % per million years) represents the first for the Unionida and could be used as a reference in future studies. [ABSTRACT FROM AUTHOR]

Understanding species distributions, and how they change in space and time, is vital when prioritising conservation or management initiatives. We assessed the distribution and density patterns of common dolphins (Delphinussp.), bottlenose dolphins (Tursiops truncatus) and Bryde’s whales (Balaenoptera edeni) in the Hauraki Gulf, New Zealand. Dedicated boat-based surveys were conducted in the inner Hauraki Gulf (IHG) and off Great Barrier Island (GBI) during 2010–2012. Generalised linear models were used to investigate temporal changes in relative densities and kernel density estimation was implemented to examine spatial trends. Common dolphins were widely distributed during all seasons, with higher densities observed during winter and spring in the IHG but during autumn off GBI. There was inter-annual variation in Bryde’s whale distribution, with high densities recorded off GBI in 2011. Bottlenose dolphins were infrequently sighted in the IHG but regularly encountered off GBI, with the highest densities during spring and summer. [ABSTRACT FROM PUBLISHER]

The viability of healthy single stranded dolphins as immediate release candidates has received little attention. Responders have been reluctant to release lone delphinids due to their social needs, even when they pass the same health evaluations as mass stranded animals. This study tracked postrelease success of 34 relocated and released satellite tagged delphinids from single and mass strandings. Three postrelease survival parameters (transmission duration, swim speed, and daily distance) were examined to evaluate whether they differed among single stranded/single released (SS/SR), mass stranded/single released (MS/SR), or mass stranded/mass released (MS/MR) dolphin groups. Comparisons were also made between healthy and borderline release candidates. Satellite tags transmitted for a mean of 21.2 d (SD = 19.2, range = 1-79), daily distance traveled was 42.0 km/d (11.25, 20.96-70.72), and swim speed was 4.3 km/h (1.1, 2.15-8.54). Postrelease parameters did not differ between health status groups, however, SS/SR dolphins transmitted for a shorter mean duration than MS/ MR and MS/SR groups. Postrelease vessel-based surveys confirmed conspecific group location for two healthy,MS/SR dolphins. Overall, these results support the potential to release healthy stranded single delphinids; however, further refinement of health assessment protocols for these challenging cases is needed. [ABSTRACT FROM AUTHOR]

Knowledge of age structure and longevity (maximum age) are essential for modelling marine mammal population dynamics. Estimation of age in common dolphins (Delphinus spp.) is primarily based on counting Growth Layer Groups (GLGs) in the dentine of thin, decalcified and stained sections of teeth. An annual incremental deposition rate was validated for Delphinus spp. 30-years ago through the use of tetracycline. However, it is not known if the pulp cavity becomes occluded in older individuals or GLGs continue to be deposited in dentine tissue. To investigate the deposition of GLGs in dentine tissue, teeth samples were obtained during the necropsies of two short-beaked common dolphins (Delphinus delphis) that were held in captivity for 31 and 33 years in New Zealand. Individuals were captured together in Hawkes Bay, North Island, New Zealand and classified as juveniles based on physical appearance. Teeth were processed in two ageing laboratories, using four different bone decalcifiers, two sectioning techniques incorporating the use of both a freezing microtome (-20°C) and paraffin microtome, and two different stains. An age was estimated for one of the dolphins, in line with that proposed based on estimated age at capture and period in captivity. However, a hypomineralised area was observed in the dentine tissue close to the pulp cavity of the second individual, preventing estimation of maximum age. The presence and structure of this anomaly is explored further within the study.

Knowledge about the maturity status of specimens included in evolutionary, taxonomic or life history investigations is fundamentally important. This study investigated the use of the degree of cranial suture fusion, the developmental status of cranial bones, and the degree of tooth wear as indicators for cranial maturity status in Delphinus sp. from New Zealand waters. In total, 15 sutures, one joint and three nonmetric characters were assessed on 66 skulls obtained from stranded and bycaught individuals sampled between 1932 and 2011. A suture index (SI) was computed based on 10 sutures, in which degree of fusion was correlated with age and the three misclassification indices (MI), calculated for a given suture, were <50%. In addition to these, five premaxilla-maxilla fusion and seven tooth wear categories were assessed. Results suggest that New Zealand Delphinus sp. skulls should be regarded as cranially mature if at least two of the following criteria are met: (1) individuals assessed as sexually mature, (2) aged ⩾ 11 yr, (3) SI ⩾ 8, and (4) premaxillamaxilla fusion ⩾ 75% of the length of the dorsal side of the rostrum. Presence of any number of rostral teeth worn to the gum line provided further evidence for cranial maturity. [ABSTRACT FROM AUTHOR]

RATIONALE: Distinguishing population units of small cetaceans continuously distributed in a widespread area is challenging but critical for their conservation and management. The use of chemical markers allows the investigation of foraging ecology and inter-specific variability, in order to detect population structure and niche segregation in the common dolphin (Delphinus spp.). METHODS: The stable isotope ratios of carbon (δ13C values) and nitrogen (δ15N values) were measured in the bone tissue of common dolphins accidentally by-caught or stranded along the north-eastern and eastern Subtropical Atlantic Ocean, by means of continuous flow elemental analyser/isotope ratio mass spectrometry. Trophic positions were determined and compared, taking into account the local ecosystem trophic baseline for each study area. Data obtained for the study areas were qualitatively compared with those for common dolphin species/populations distributed worldwide. RESULTS: The δ13C and δ15N values were higher in the eastern Subtropical Atlantic as a consequence of the coexistence in the area of the common dolphin short- and long-beaked morphotypes. Individuals from the north-eastern Atlantic displayed lower δ15N values, reflecting dissimilarities in diet and variation in local isotopic baselines. Comparisons with other areas around the world suggest that the species is extremely adaptive and feeds at different trophic levels to adapt to local variations. CONCLUSIONS: Stable isotopes are a useful tool to investigate population structure and trophic niche segregation. The trophic behaviour of worldwide populations of common dolphins was fruitfully analysed and revealed substantial differences, probably reflective of both adaptive strategies of the genus and dissimilarities in the structure of the ecosystems. [ABSTRACT FROM AUTHOR]

Genetic studies have shown that there are small but significant differences between the short-beaked common dolphin populations in the Atlantic Ocean and those in the Mediterranean Sea. The short-beaked common dolphin is a highly vocal species with a wide sound production repertoire including whistles. Whistles are continuous, narrowband, frequency-modulated signals that can show geographic variation in dolphin species. This study tests whether the differences, highlighted by genetic studies, are recognisable in the acoustic features of short-beaked common dolphin’s whistles in the two adjacent areas of the Atlantic Ocean and the Mediterranean Sea. From a selected sample of good quality whistles (514 recorded in the Atlantic and 193 in the Mediterranean) 10 parameters of duration, frequency and frequency modulation were measured. Comparing data among basins, differences were found for duration and all frequency parameters except for minimum frequency. Modulation parameters showed the highest coefficient of variation. Through discriminant analysis we correctly assigned 75.7% of sounds to their basins. Furthermore, micro-geographic analysis revealed similarity between the sounds recorded around the Azores and the Canary archipelagos and between the Bay of Biscay and the Mediterranean Sea. Results are in agreement with the hypothesis proposed by previous genetic studies that two distinct populations are present, still supposing a gene flow between the basins. This study is the first to compare short-beaked common dolphin’s whistles of the Atlantic Ocean and the Mediterranean areas. [ABSTRACT FROM PUBLISHER]

The current paucity of published blood values and other clinically relevant data for short-beaked common dolphins, Delphinus delphis, hinders the ability of veterinarians and responders to make well-informed diagnoses and disposition decisions regarding live strandings of this species. This study examined hematologic, clinical chemistry, and physical parameters from 26 stranded common dolphins on Cape Cod, Massachusetts, in light of their postrelease survival data to evaluate each parameter's efficacy as a prognostic indicator. Statistically and clinically significant differences were found between failed and survived dolphins, including lower hematocrit, hemoglobin, TCO2, and bicarbonate and higher blood urea nitrogen, uric acid, and length-to-girth ratios in animals that failed. In general when compared to survivors, failed dolphins exhibited acidosis, dehydration, lower PCVs, and decreased body condition. Additionally, failed dolphins had the highest ALT, AST, CK, LDH, GGT, and lactate values. These blood values combined with necropsy findings indicate that there are likely a variety of factors affecting postrelease survival, including both preexisting illness and stranding-induced conditions such as capture myopathy. Closer evaluation of these parameters for stranded common dolphins on point of care analyzers in the field may allow stranding personnel to make better disposition decisions in the future. [ABSTRACT FROM AUTHOR]

New Zealand is the southernmost limit of the common dolphin's (genus Delphinus) distribution in the Pacific Ocean. In this area, common dolphins occur in both coastal and oceanic habitats, exhibit seasonal and resident occurrence, and present high morphological variability. Here we investigated the population structure and the taxonomic identity of common dolphins ( Delphinus sp.) within New Zealand waters using 14 microsatellite loci, 577 bp of the mt DNA control region, and 1,120 bp of the mt DNA cytochrome b gene across 90 individuals. We found high genetic variability and evidence of population expansion. Phylogenetic analyses conducted to clarify the taxonomic status of New Zealand common dolphins did not show any clustering reflecting geographic origin or morphotypes. The microsatellite analysis showed genetic differentiation between Coastal and Oceanic putative populations, while mt DNA revealed significant genetic differentiation only between the Hauraki Gulf and other putative groups. Our results suggest that differences in habitat choice and possible female site fidelity may play a role in shaping population structure of New Zealand common dolphins. [ABSTRACT FROM AUTHOR]

Molecular phylogenetic analyses conducted over the past 15 yr have consistently had difficulties resolving relationships among the cetacean species in the subfamily Delphininae. In addition, paraphyly of the genera Tursiops and Stenella in these molecular phylogenies has been a recurrent problem since the first appearance of such a phylogeny in 1999, suggesting that these genera do not accurately reflect the evolutionary relationships of the species they contain. Morphological analyses have not resolved the issues. The genera in Delphininae originated in the 19th Century on questionable morphological grounds. The species were nearly all originally described in the genus Delphinus of Linnaeus. Recent molecular phylogenies based on various mitochondrial and nuclear DNA markers have suggested a wide range of possible relationships among these taxa, and several authors have suggested synonymizing all the taxa ( Lagenodelphis, Stenella, Sousa, and Tursiops) under Delphinus. Until molecular and/or morphological analyses adequately sort out relationships in this very recently radiated group, one possible solution indeed would be to merge all the delphinine genera with Delphinus. Implications of such a move and alternatives are discussed. [ABSTRACT FROM AUTHOR]

Molecular assays were used to determine the sex of 1,294 biopsied common dolphins (658 long-beaked common dolphins, Delphinus capensis, and 636 short-beaked common dolphins, D. delphis) in the Southern California Bight. Sex ratio differed substantially between the two species; females comprised 241 (36.6%) of D. capensis samples and 410 (64.5%) of D. delphis samples. All biopsies were taken either from a large research ship or from a small, rigid-hull inflatable boat ( RHIB) launched from the larger ship. When conducting replicate biopsy effort on the same schools from each vessel/platform ('Tandem Biopsy Sampling'), we found evidence that disproportionately more female D. capensis were biopsied from the RHIB than from the ship but the same was not true for D. delphis. We suspect that these results are driven by bowriding-behavior differences between the two species. Biopsy duration, geographic location, school size, and Julian date were considered as potential covariates with sex ratio; geographic location was the only one to show strong evidence of correlation. This study also presents an alternative to the erroneous practice of comparing sex ratios to a theoretical assumption of parity ( i.e., 50:50 sex ratio) when researchers avoid sampling animals paired with calves. [ABSTRACT FROM AUTHOR]

While coastal cetaceans can become habituated to watercraft, that may not prevent their injury or mortality as a consequence of vessel strike. Here we report a case of a likely collision between a Common Dolphin Delphinus sp. and a recreational vessel in the Hauraki Gulf, New Zealand. Injuries sustained by the immature male dolphin were fatal. Recovery and subsequent post-mortem of the carcass revealed a transection of the spinal cord, with the vertebral column sustaining fractures between L17 and Cd7 and between Cd3 and Cd8 of the neural and transverse processes, respectively. Cd4 likely received the brunt of the impact given the vertebral body and epiphyses were also fractured. Paralysis of the lower truck and associated extensive internal injuries resulted in a live stranding and subsequent mortality. Injuries sustained were consistent of those of blunt force trauma, a consequence of an impact caused by a collision with a small watercraft, most likely a jet-ski. This incident reinforces the need for continued public education concerning safe water practices around marine mammals, which are protected under the New Zealand Marine Mammals Protection Act 1978 and Marine Mammals Protection Regulations 1992. [ABSTRACT FROM AUTHOR]

The health, postrelease movements, and behavior of mass stranded Atlantic white-sided dolphins ( Lagenorhynchus acutus) and short-beaked common dolphins ( Delphinus delphis) from Cape Cod, Massachusetts, were evaluated. Health was assessed through physical examination and blood analysis. Eleven dolphins (eight white-sided dolphins and three common dolphins) were relocated, outfitted with satellite transmitters, and released during seven mass stranding events. Five transmitters recorded only location, and six also included a time-depth recorder. Transmission duration ranged from 8 h to 218 d, with a mean of 117 d (median = 118 d, SD = 82 d), after release. All dolphins demonstrated extensive movement throughout the Gulf of Maine. The distribution of tagged dolphins was considered normal based on comparisons with published data for these species. Excluding the dolphin that transmitted for only 8 h, mean minimum speeds for individual dolphins ranged from 3.4 to 6.6 km/h; overall mean for all dolphins was 5.4 km/h (SD = 0.9 km/h). The five dolphins with time-depth recorders had mean dive depths of 8.6-40.3 m and mean dive durations of 46-296 s. Hematologic and biochemical data revealed only minor abnormalities. Data suggest that at least 10 of the 11 dolphins were likely successfully reintroduced into the wild. [ABSTRACT FROM AUTHOR]

The article discusses a study which investigated morphological vascular proliferation in a set of common dolphins stranded in the Canary Islands coats during a 10 year period. Topics discussed include the detection of focal or multifocal angiomatosis-like lesions in common dolphins, a high association between vascular proliferation and parasitic infestation and the presentation of a single pulmonary cavernous hemangioma.

The abundance of the long-beaked common dolphin (Delphinus capensis) is estimated from data collected during a 2009 ship-based line-transect survey. The survey was designed to provide fine-scale coverage of the known range of D. capensis along the California and west Baja California coasts. Estimates of D. capensis abundance presented are the highest to date for California waters and may reflect a combination of improved survey design for this species and increasing numbers of D. capensis in state waters. Estimates of D. capensis abundance within California waters are 183,396 (CV50.41, 95% CI 78,149 2 379,325) animals. An additional 95,786 (CV50.47, 95% CI 36,881 2 209,507) D. capensis were estimated in Baja California waters from the U.S./Mexico border south to the tip of Baja California. Total estimated abundance of D. capensis in California and Baja California west coast waters is 279,182 (CV50.31, 95% CI 148,753 2 487,323) animals. [ABSTRACT FROM AUTHOR]

The article discusses a study on sex ratio variations in biopsy samples of bottlenose dolphins Tursiops truncatus, spotted dolphins Stenella frontalis and common dolphins Delphinus delphis around the Portuguese archipelagoes of the Azores and Medeira. It states that there was substantially lower female proportion in the sample. Population structures were said to be inadequately reflected in the observed sex ratios. The Azores sampling process was found to have a stronger influence than in Madeira. Biopsy sampling is not recommended for sex ratio estimation in natural populations.

1. The common dolphins (genus Delphinus) have one of most problematic taxonomies and complex distribution patterns of all cetaceans. Although the taxonomy and the distribution seem to have been clarified somewhat in the eastern North Pacific and Indo-Pacific Oceans, many questions remain in the Southwestern Atlantic Ocean (SWA). We review the biogeography of Delphinus in the SWA. 2. We reviewed data from strandings, incidental catches and sightings since 1922. Systematic surveys were conducted in five major areas. Twenty-one natural history collections were examined, and 135 skulls were measured. 3. A total of 184 records of common dolphins were compiled. Delphinus apparently occurs in three stocks in the SWA: one located in northern Brazil and two from southeastern Brazil (∼22°S) to central Argentina (∼42°S). Two distinct patterns in habitat use were observed by depth: in southeastern Brazil, sightings were restricted to coastal waters with water depths ranging from 18m to 70m. On the other hand, in the area that extends from southern Brazil to Central Argentina (from 28°S to 42°S), sightings were recorded in deeper waters, ranging from 71m to 1435m, with the exception of occasional coastal sightings. The cranial analyses demonstrated that both short-beaked common dolphins Delphinus delphis and long-beaked common dolphins Dephinus capensis occur in the SWA. 4. In the SWA, Delphinus seems to occur near areas of high productivity. One stock is associated with the productive waters discharged by the Amazon River and possibily with the coastal upwelling system off the coast of Venezuela, while the other stocks are associated with the Cabo Frio upwelling system and the Subtropical Convergence. Our results indicate that the current taxonomy does not adequately reflect the amount of variation within the genus in the world. [ABSTRACT FROM AUTHOR]

An initial inventory of the dolphins and whales occurring in Guinea's coastal waters is documented primarily from specimens and photographic evidence obtained from strandings and by-catches. Seven species are fully validated, four odontocetes, Tursiops truncatus, Sousa teuszii, Stenella frontalis, Kogia breviceps and three balaenopterid whales: Balaenoptera brydei, Balaenoptera acutorostrata and Megaptera novaeangliae. Another three reported species (Globicephala macrorhynchus, Steno bredanensis and Delphinus delphis) are insufficiently supported but thought to be valid. Small cetaceans landed as by-catch and a stranded whale were used for human consumption, but no evidence of substantial takes, directed or by-catch, was found. However, concern is raised about even minimal takes of the vulnerable Atlantic humpback dolphin. The seasonal presence of three confirmed humpback whales, two strandings (July and September) and a sighting (October), is synchronous with the species' southern hemisphere wintering/breeding season in low latitudes. We hypothesize that these whales may comprise the north-westernmost range of the population that breeds/overwinters in coastal waters of the Bight of Benin, northern Gulf of Guinea. [ABSTRACT FROM AUTHOR]

Due to indications that misidentification (largely confusion among dolphins of the genera Delphinus and Stenella) in the past had led to erroneous assumptions of distribution of the two species of common dolphins ( Delphinus delphis and D. capensis) in the western Atlantic Ocean, we conducted a critical re-examination of records of the genus Delphinus from this region. We compiled 460 ‘plottable’ records, required support for confirmation of genus and species identifications, and found many records lacking (and some clearly misidentified). When we plotted only the valid records ( n = 364), we found evidence of populations in only three areas, and apparent absence throughout much of the tropical/subtropical regions. Off the east coast of the US and Canada, D. delphis is found from the Georgia/South Carolina border (32°N) north to about 47–50°N off Newfoundland. Since the 1960s, they have apparently been absent from Florida waters. There is no evidence that dolphins of the genus occur in the Gulf of Mexico. Reports of common dolphins from most of the Caribbean Basin are also rejected, and the only place in that region where they are confirmed to occur is off central-eastern Venezuela (a coastal D. capensis population). Off eastern South America, common dolphins appear to be restricted to south of 20°S. There is a coastal long-beaked population found in the South Brazil Bight, and one or more short-beaked populations south and offshore of this (ranging south to at least northern Argentina). The results are very different from commonly-accepted patterns of distribution for the genus in the Atlantic. Most areas of distribution coincide with moderate to strong upwelling and common dolphins appear to avoid warm, tropical waters. This study shows that great care must be taken in identification of similar-appearing long-beaked delphinids, and that uncritical acceptance of records at face value can lead to incorrect assumptions about the ranges of the species involved. [ABSTRACT FROM AUTHOR]