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Assessing the health of marine mammal sentinel species is crucial to understanding the impacts of environmental perturbations on marine ecosystems and human health. In Arctic regions, beluga whales, Delphinapterus leucas , are upper level predators that may serve as a sentinel species, potentially forecasting impacts on human health. While gene expression profiling from blood transcriptomes has widely been used to assess health status and environmental exposures in human and veterinary medicine, its use in wildlife has been limited due to the lack of available genomes and baseline data. To this end we constructed the first beluga whale blood transcriptome de novo from samples collected during annual health assessments of the healthy Bristol Bay, AK stock during 2012–2014 to establish baseline information on the content and variation of the beluga whale blood transcriptome. The Trinity transcriptome assembly from beluga was comprised of 91,325 transcripts that represented a wide array of cellular functions and processes and was extremely similar in content to the blood transcriptome of another cetacean, the bottlenose dolphin. Expression of hemoglobin transcripts was much lower in beluga (25.6% of TPM, transcripts per million) than has been observed in many other mammals. A T12A amino acid substitution in the HBB sequence of beluga whales, but not bottlenose dolphins, was identified and may play a role in low temperature adaptation. The beluga blood transcriptome was extremely stable between sex and year, with no apparent clustering of samples by principle components analysis and < 4% of genes differentially expressed (EBseq, FDR < 0.05). While the impacts of season, sexual maturity, disease, and geography on the beluga blood transcriptome must be established, the presence of transcripts involved in stress, detoxification, and immune functions indicate that blood gene expression analyses may provide information on health status and exposure. This study provides a wealth of transcriptomic data on beluga whales and provides a sizeable pool of preliminary data for comparison with other studies in beluga whale. [ABSTRACT FROM AUTHOR]

The biodiversity of the Mediterranean Sea is undergoing important changes. Cetaceans, as top predators, are an important component of marine ecosystems. The seasonal distribution and abundance of several cetacean species were studied with a large aerial survey over the North-Western Mediterranean Sea, including the international Pelagos sanctuary, the largest Marine Protected Area (MPA) designed for marine mammals in the Mediterranean. A total of 8 distinct species of cetaceans were identified, and their occurrence within the sanctuary was investigated. Abundance estimates were obtained for three groups of species: the small delphinids (striped dolphins mainly), the bottlenose dolphin and the fin whale. There was a seasonal variation in striped dolphin abundance between winter (57,300 individuals, 95% CI: 34,500–102,000) and summer (130,000, 95% CI: 76,800–222,100). In contrast, bottlenose dolphin winter abundance was thrice that of summer. It was also the only species to exhibit any preference for the Pelagos sanctuary. Fin whale abundance had the reverse pattern with winter abundance (1000 individuals, 95% CI: 500–2500) and summer (2500 individuals, 95% CI: 1500–4300), without any preference for the sanctuary. Risso's dolphins, pilot whales and sperm whales did not exhibit strong seasonal pattern in their abundance. These results provide baseline estimates which can be used to inform conservation policies and instruments such as the Habitats Directive or the recent European Marine Strategy Framework Directive. [ABSTRACT FROM AUTHOR]

The Adriatic Sea is one of the areas most exposed to trawling, worldwide. We used four years (2018–2021) and 19,887 km of survey data to investigate factors influencing daylight dolphin distribution in its north-western sector, where common bottlenose dolphins Tursiops truncatus routinely follow fishing trawlers. We validated Automatic Identification System information on the position, type and activity of three types of trawlers based on observations from boats, and incorporated this information in a GAM-GEE modelling framework, together with physiographic, biological and anthropogenic variables. Along with bottom depth, trawlers (particularly otter and midwater trawlers) appeared to be important drivers of dolphin distribution, with dolphins foraging and scavenging behind trawlers during 39.3% of total observation time in trawling days. The spatial dimension of dolphin adaptations to intensive trawling, including distribution shifts between days with and without trawling, sheds light on the magnitude of ecological change driven by the trawl fishery. • Bottlenose dolphins routinely follow fishing trawlers in the NW Adriatic Sea. • Boat surveys (19,887 km) to investigate dolphin distribution in years 2018–2021. • Field validation of Automatic Identification System data (three types of trawlers). • Modelling framework with physiographic, biological and anthropogenic variables. • Trawling drives dolphin distribution; shifts between days with and without trawling. [ABSTRACT FROM AUTHOR]

The aim of the present study was to describe the size and composition of groups of common bottlenose dolphins (Tursiops truncatus) in the Cagarras Archipelago (23°01’S, 43°12’W), Rio de Janeiro, Brazil based on six years of observation (2004 and 2006 to 2010). The group size (n = 51) ranged between three and 30 individuals (mean = 13.7 ± 7.1), and the frequency distribution of group size showed modes at six individuals and 19 individuals. The largest average group size occurred in 2004 (mean 21.4 ± 3.3) and the smallest in 2008 (mean 4.4 ± 0.8). The number of individuals/group decreased over the years and this decrease could be correlated with habitat quality. The average number of immature individuals (neonates, calves and juveniles), expressed as a proportion of the total group size, varied between 0.31 (2006) and 0.4 (2010). This proportion did not vary significantly among years. These results suggest that the Cagarras Archipelago should be considered critical habitat for the survival and /or population growth of T. truncatus in southeastern Brazil.

The common bottlenose dolphin (Tursiops truncatus) is the only cetacean present in the semiclosed waters of the Gulf of Ambracia, Western Greece. This increasingly degraded coastal ecosystem hosts one of the highest observed densities in the Mediterranean Sea for this species. Photo-identification data and tissue samples collected through skin-swabbing and remote biopsy sampling techniques during boat-based surveys conducted between 2006 and 2015 in the Gulf, were used to examine bottlenose dolphin abundance, population trends, site fidelity, genetic differentiation and toxicological status. Bottlenose dolphins showed high levels of year-round site fidelity throughout the 10-year study period. Dolphin population estimates mostly fell between 130 and 170 with CVs averaging about 10%; a trend in population size over the 10 years was a decline of 1.6% per year (but this was not significant). Genetic differentiation between the bottlenose dolphins of the Gulf and their conspecifics from neighbouring populations was detected, and low genetic diversity was found among individuals sampled. In addition, pesticides where identified as factors posing a real toxicological problem for local bottlenose dolphins. Therefore, in the Gulf of Ambracia, high dolphin density does not seem to be indicative of favourable conservation status or pristine habitat. [ABSTRACT FROM AUTHOR]

Degradation of coastal and estuarine habitats is probably inevitable when more people move to coastal regions. To determine potential effects of habitat degradation on a species, the extent of exposure due to habitat fidelity and any characteristics that make the habitat preferable need to be identified. Common bottlenose dolphin (Tursiops truncatus) density and distribution in northeastern Florida were seasonally heterogeneous in 1994 through 1997. Regional and seasonal fidelity patterns and habitat variable preferences (e.g., salt marsh, residential density, etc.) of individual dolphins were examined to determine if this heterogeneity was due to significant preferences. Thirty-six bottlenose dolphins were sighted more than expected (preferred) in estuarine waters north (ICN) of the St. Johns River (SJR), whereas 87 dolphins preferred estuarine waters south (ICS) of the SJR. Of dolphins with an ICN preference, 78% exhibited no preference for water season. In contrast, 93% of dolphins with an ICS preference exhibited cold season avoidance. Dolphins exhibited specific preference and avoidance patterns for specific habitat variables. Although undeveloped habitats comprised the majority of total area available within the ICN (94%) and ICS/SJR (54%) regions, less than 25 and 7%, respectively, of the dolphins preferred these ICN and ICS/SJR habitats. Regional, seasonal, and habitat variable preferences, such as those identified in this study, result in different levels to which highly mobile bottlenose dolphins may be affected by changes in habitat suitability. Lack of measurable fidelity observed for bottlenose dolphins sighted in alongshore coastal waters suggests reduced susceptibility of this community to anthropogenic habitat changes in northeastern Florida. In contrast, the highly philopatric nature of dolphins in the ICN increases their vulnerability to habitat changes and degradation. Seasonal use of the SJR and ICS regions of northeastern Florida, on the other hand, may mitigate the impact of habitat changes and degradation experienced by dolphins preferring these regions. [ABSTRACT FROM AUTHOR]

We report on the removal of foreign objects from the forestomach of a 200 kg adult male common bottlenose dolphin (Tursiops truncatus) in the Seoul zoo using a modified stainless steel hook and flexible wire snare attached to a gastrointestinal fiberoptic endoscope. The foreign bodies included a 10 × 3.5 cm plastic tube, 4 × 2.0 cm stainless steel pipe, brush, and concrete debris. Our technique using a stainless steel wire hook and snare attached to a gastroscope can be used to remove foreign objects from the forestomach of common bottlenose dolphins.

Harmful algal blooms (HABs), which can be lethal in marine species and cause illness in humans, are increasing worldwide. In the Gulf of Mexico, HABs of Karenia brevis produce neurotoxic brevetoxins that cause large-scale marine mortality events. The long history of such blooms, combined with the potentially severe effects of exposure, may have produced a strong selective pressure for evolved resistance. Advances in next-generation sequencing, in particular genotyping-by-sequencing, greatly enable the genomic study of such adaptation in natural populations. We used restriction site-associated DNA (RAD) sequencing to investigate brevetoxicosis resistance in common bottlenose dolphins (Tursiops truncatus). To improve our understanding of the epidemiology and aetiology of brevetoxicosis and the potential for evolved resistance in an upper trophic level predator, we sequenced pools of genomic DNA from dolphins sampled from both coastal and estuarine populations in Florida and during multiple HAB-associated mortality events. We sequenced 129 594 RAD loci and analysed 7431 single nucleotide polymorphisms (SNPs). The allele frequencies of many of these polymorphic loci differed significantly between live and dead dolphins. Some loci associated with survival showed patterns suggesting a common genetic-based mechanism of resistance to brevetoxins in bottlenose dolphins along the Gulf coast of Florida, but others suggested regionally specific mechanisms of resistance or reflected differences among HABs. We identified candidate genes that may be the evolutionary target for brevetoxin resistance by searching the dolphin genome for genes adjacent to survival-associated SNPs. [ABSTRACT FROM AUTHOR]

A number of studies were initiated in response to the Deepwater Horizon (DWH) oil spill to understand potential injuries to bottlenose dolphins ( Tursiops truncatus ) that inhabit the northern Gulf of Mexico (NGoM) estuarine waters. As part of these studies, remote biopsy skin and blubber samples were collected from dolphins at six field sites that received varying degrees of oiling: Barataria Bay (BB), Chandeleur Sound West (CSW), Chandeleur Sound East (CSE), Mississippi Sound South (MSS), Mississippi Sound North (MSN), and St. Joseph Bay (SJ). Blubber samples from 108 male dolphins were analyzed for persistent organic pollutant (POP) concentrations, as high levels of POPs have been previously reported in other southeastern U.S. dolphins and the potential contribution of these compounds to adverse health effects in NGoM dolphins must be considered. Dolphin blubber levels of summed POPs (ΣPOPs) did not differ significantly across sites ( F -test, P = 0.9119) [μg/g lipid; geometric mean and 95% CI]; CSW [65.9 (51.4–84.6)], SJ [74.1 (53.0–104)], MSN [74.3 (58.7–93.9)], BB [75.3 (56.4–101)], CSE [80.5 (57.8–112)], and MSS [82.5 (65.9–103)]. Overall, POP concentrations were in the lower half of the range compared to previously reported concentrations from other southeastern U.S. sites. Increased dolphin mortalities have been ongoing in the NGoM and have been suggested to be linked with the DWH oil spill. In addition, lung disease, impaired adrenal function, and serum biochemical abnormalities have been reported in dolphins from BB, an area that was heavily oiled. The results of this study suggest that POPs are likely not a primary contributor to the poor health conditions and increased mortality observed in some populations of NGoM dolphins following the DWH oil spill. [ABSTRACT FROM AUTHOR]

It is increasingly common to monitor the marine environment and establish geographic trends of environmental contamination by measuring contaminant levels in animals from higher trophic levels. The health of an ecosystem is largely reflected in the health of its inhabitants. As an apex predator, the common bottlenose dolphin ( Tursiops truncatus ) can reflect the health of near shore marine ecosystems, and reflect coastal threats that pose risk to human health, such as legacy contaminants or marine toxins, e.g. polychlorinated biphenyls (PCBs) and brevetoxins. Major advances in the understanding of dolphin biology and the unique adaptations of these animals in response to the marine environment are being made as a result of the development of cell-lines for use in in vitro experiments, the production of monoclonal antibodies to recognize dolphin proteins, the development of dolphin DNA microarrays to measure global gene expression and the sequencing of the dolphin genome. These advances may play a central role in understanding the complex and specialized biology of the dolphin with regard to how this species responds to an array of environmental insults. This work presents the creation, characterization and application of a new molecular tool to better understand the complex and unique biology of the common bottlenose dolphin and its response to environmental stress and infection. A dolphin oligo microarray representing 24,418 unigene sequences was developed and used to analyze blood samples collected from 69 dolphins during capture-release health assessments at five geographic locations (Beaufort, NC, Sarasota Bay, FL, Saint Joseph Bay, FL, Sapelo Island, GA and Brunswick, GA). The microarray was validated and tested for its ability to: 1) distinguish male from female dolphins; 2) differentiate dolphins inhabiting different geographic locations (Atlantic coasts vs the Gulf of Mexico); and 3) study in detail dolphins resident in one site, the Georgia coast, known to be heavily contaminated by Aroclor 1268, an uncommon polychlorinated (PCB) mixture. The microarray was able to distinguish dolphins by sex, geographic location, and corroborate previously published health irregularities for the Georgia dolphins. Genes involved in xenobiotic metabolism, development/differentiation and oncogenic pathways were found to be differentially expressed in GA dolphins. The report bridges the advancements in dolphin genome sequencing to the first step towards providing a cost-effective means to screen for indicators of chemical toxin exposure as well as disease status in top level predators. [ABSTRACT FROM AUTHOR]

1. There is a resident common bottlenose dolphin population inhabiting theKvarnerić area of the northern Adriatic Sea, Croatia. The observed decline in population size between 1995 and 2003 led to the declaration of a part of the Kvarnerić as the Cres-Lošinj Special Marine Reserve (CLSMR) in 2006. Protection lasted 3 years, before lapsing. 2. A boat based photo-identification study was conducted between 2004 and 2011 with the aim to estimate the number of bottlenose dolphins inhabiting the CLSMR area, investigate the factors influencing their habitat use and explore the possibility that this area is representative of the population for the whole Kvarnerić. 3. Standard mark-recapture methods and theMth estimator of Chao for closed populations were applied. The lowest value was estimated in 2008 (N=112; 95% CI=94-150) and the highest in 2006 (N=310; 95% CI=265-392). The statistically significant inter-annual variability is likely to reflect natural and anthropogenic driven shifts in habitat use rather than real changes in population size. 4. The average monthly sighting rate was lower in the tourist season (Jun-Aug) than in the pre- and post touristseason, suggesting that developed nautical tourism may influence shifts in habitat use. Other potential causes are distribution of prey and fishing effort. 5. Inclusion of data from the rest of the Kvarnerić for the years of 2005 and 2011 did not reveal a significant increase in estimated abundance (2005: z=-0.413, P=0.3398; 2011: z =-1.749, P=0.0401). This indicates that the CLSMR area is representative of the whole Kvarnerić. 6. The number of bottlenose dolphins using the CLSMR area seems to have increased compared with the previous study (1995-2003). This could be due to a shift in habitat use or an increase in population size. However, yearly variations indicate processes causing displacements within the dolphin population home range. Conservation measures aiming at reducing the displacements are proposed. [ABSTRACT FROM AUTHOR]

In coastal marine ecosystems, neurotoxins produced by harmful algal blooms (HABs) often result in large-scale mortality events of many marine species. Historical and frequent exposure to HABs therefore may provide a strong selective pressure for adaptations that result in toxin resistance. Neurotoxin resistance has independently evolved in a variety of terrestrial and marine species via mutations in genes encoding the toxin binding sites within the voltage-gated sodium channel gene complex. Accordingly, we tested the hypothesis that genetic variation in the putative binding site of brevetoxins in common bottlenose dolphins ( Tursiops truncatus ) explains differences among individuals or populations in resistance to harmful Karenia brevis blooms in the Gulf of Mexico. We found very little variation in the sodium channel exons encoding the putative brevetoxin binding site among bottlenose dolphins from central-west Florida and the Florida Panhandle. Our study included samples from several bottlenose dolphin mortality events associated with HABs, but we found no association between genetic variation and survival. We observed a significant effect of geographic region on genetic variation for some sodium channel isoforms, but this can be primarily explained by rare private alleles and is more likely a reflection of regional genetic differentiation than the cause of different levels of HAB resistance between regions. In contrast to many other previously studied neurotoxin-resistant species, we conclude that bottlenose dolphins have not evolved resistance to HABs via mutations in genes encoding the brevetoxin binding site on the voltage-gated sodium channels. [ABSTRACT FROM AUTHOR]

The conditioning of dolphins to human-interaction behaviors has been documented in several areas worldwide. However, the metrics used to report human-interaction behaviors vary among studies, making comparison across study areas difficult. The purpose of this study was to develop standard metrics for reporting human-interaction behaviors and utilize these metrics to quantify the prevalence of human-interaction behaviors by common bottlenose dolphins ( Tursiops truncatus) near Savannah, Georgia. The four metrics used were percentage of days with human-interaction behaviors, percentage of sightings with human-interaction behaviors, percentage of the catalog that interacted with humans, and spatial extent of human-interaction behaviors. Human-interaction behaviors were observed on 69.6% of days and 23.5% of sightings near Savannah. In addition, 20.1% of the animals in the catalog were observed interacting with humans. These rates are much higher than those found in other areas with known issues with human-interaction behaviors. These behaviors were observed across an area of 272.6 km2, which is larger than other reported areas. The four metrics used in this study proved to be a valuable way to report human-interaction behaviors, and their use is recommended for future studies to allow for comparison among areas. [ABSTRACT FROM AUTHOR]

Levels of 24 organochlorine compounds, including toxic mono- ortho PCB congeners, were determined in the organs and tissues (blubber, kidney, lung, muscle, liver, heart) of 13 common bottlenose dolphins ( Tursiops truncatus ) stranded between 2000 and 2005 in the northern part of the Croatian territorial waters of the Adriatic Sea. Polychlorinated biphenyls (PCBs) were found at higher concentrations in comparison with organochlorine pesticides (OCPs) in all of the analyzed tissues. Sums of six indicator congeners (Σ6PCB) constituted around 50% of the total PCB amount, while PCB-153 and PCB-138 were found to have the highest concentrations. Among the seven investigated OCPs, p , p ′-DDE was found at the highest concentrations. In blubber, mean values of 22,048 and 11,310 ng g −1 wet weight were determined for ΣPCB and ΣDDT, respectively. Much lower concentrations were found in muscle samples, followed by similar concentrations in kidneys, liver and heart, while the lowest levels of organochlorine contaminants were found in lungs. The results indicate that p , p ′-DDT is still being introduced in the Mediterranean region. PCB concentrations are among the highest found in this region and toxicological assessments indicate that the health of this specie is at high risk. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea common bottlenose dolphin population has been assessed as Vulnerable according to the IUCN Red List Criteria. The species is also included in several International Agreements, European Union Regulations and Directives. Amongst them, a strict protection and identification of special conservation areas are requested by the EU Habitats Directive. Despite direct takes, by-catch, chemical and acoustic pollution, and prey depletion, general habitat degradation and fragmentation have been indicated as detrimental for the species, the degree to which these threats pose population risk is still largely unknown. At present it is thus not possible to depict the actual status of the population and to assess prospective trends. To address this gap in the current knowledge, line transect distance sampling aerial surveys were conducted in a wide portion of the Western Mediterranean Sea between the summer of 2010 and winter 2011. A total of 165 parallel transects equally spaced at 15 km were designed providing homogeneous coverage probability. Overall, 21,090 km were flown on effort and 16 bottlenose dolphin sightings were recorded and used for the analysis. The surface abundance and density estimates resulted in 1676 animals (CV = 38.25; 95% CI = 804–3492) with a density of 0.005 (CV = 38.25%). These results represent the first ever estimates for the common bottlenose dolphin over a wide portion of the Western Mediterranean Sea Subregion, with the potential to be useful baseline data to inform conservation. Specifically, they could be used as indicators under the Marine Strategy Framework Directive requirements, in conjunction with other study methods. [ABSTRACT FROM AUTHOR]

Common bottlenose dolphin (CBD) and bottom trawlers exploit the same ecological niche. The estimated CBD population along the Israeli coastline consumes roughly 1280 t of prey annually, similar to the mean annual trawl-fishery yield of 1300 t. In the ultra-oligotrophic Levantine Basin, the potential for competition for limited resources therefore exists. We aimed to examine whether the two consumers indeed harvest the same trophic level of the food web and the same members of that level. These questions were addressed by stomach content and stable isotope (δ15N and δ13C) analyses. The database included 26 prey-containing stomachs collected between 1996 and 2008 and muscle tissue samples of 23 dolphins and of 27 species of commercial fish and invertebrates for stable isotopes analysis. The 59.3 kg combined stomach content included at least 754 prey items, 97.3% of which were fish, belonging to 22 identified species. About half (46.4%) of the prey mass had medium-to-high commercial value. The overall similarity of the composition of the pooled biomass and that of the average commercial catch was expressed by a Pianka index of 0.49. Sparidae (sea bream) was the only family important for both consumers. The mean δ15N value of CBD muscle was found to be relatively low compared to other geographical areas and the estimated mean δ15N of its diet fell below that of most commercial species tested. Our findings suggest that CBD and the fisheries only partly share resources, with CBD having an overall minor effect on the bottom trawl fishery, mainly on the Sparidae catch. [ABSTRACT FROM PUBLISHER]

Cetacean morbillivirus (CeMV) has caused several epizootics in multiple species of cetaceans globally and is an emerging disease among cetaceans in Australia. We detected CeMV in 2 stranded coastal Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Western Australia. Preliminary phylogenetic data suggest that this virus variant is divergent from known strains. [ABSTRACT FROM AUTHOR]

In the United States, interactions between the shrimp trawl fishery and bottlenose dolphins are known to exist; however, the level of mortality is largely unknown, and has not been studied in South Carolina, USA. The current study attempted to determine if interactions between bottlenose dolphins and the South Carolina commercial shrimp trawl fishery pose a significant threat to dolphin populations and if fishery related mortality is underreported. Onboard observations were made during a 25 day (August-December 2010) field study. No dolphin takes occurred during the observational period. These observations focused on direct physical interactions with the gear and depredation behaviours. Additionally, a subsample of the shrimp fishery in South Carolina was asked to participate in a mailed survey. The survey included questions related to gear, dolphin observations, and the status of the shrimp fishery. This paper also examines historical dolphin stranding data from the NOAA/CCEHBR MMIS database for signs of shrimp fishery interactions. A three-tiered flow diagram was developed to characterise each stranding case according to the likelihood that mortality resulted from trawler interaction. Field results point to significant dolphin presence around commercial trawlers (x2 = 23.406, p < 0.001). Survey results showed 12 unreported incidents of shrimp trawl fishery mortality of dolphins. Finally, stranding records revealed several more cases with signs of possible trawler interaction. The current US National Marine Fisheries Service (NOAA) designation of the fishery as a Category II fishery is correct. Increased observer coverage and improved communication with the fishery on the importance of reporting takes is warranted. [ABSTRACT FROM AUTHOR]

The increase in fishing effort and the expansion of the fishing grounds of small-scale fisheries increase the interactions with marine mammals globally. Such interactions are poorly understood since data is difficult to obtain. The aim of this study is to infer the interactions between small-scale fisheries and marine mammals, based on the fisher's perspective. We used the southern coast of Chiapas, Mexico as the location for the model. A total of 56 interviews and eight fishery trips were conducted in three fishing communities. Fishing vessels are 7 m long with an outboard engine with 58.9% of fishers using gillnets and 21.4% using longlines. Fishers were able to identify three marine mammal species in their fishing grounds: Tursiops truncatus , Stenella longirostris , and Stenella attenuata graffmani. However, based on photographs, fishers identified seven additional species. Tursiops truncatus interacts negatively with their fishing activities by stealing fish, ripping nets, interfering during sets, and stealing bait from longlines, which fosters a negative perception among fishers. Despite this, fishers implement low-impact mitigation measures. A Canonical Correspondence Analysis revealed the adverse impact of the common bottlenose dolphin on Scomberomorus sierra fishing with gillnets at the coastal zone. The presence of S. longirostris centroamericana and S. attenuata graffmani has a positive impact on the fishery because are indicators of fish schools. The perception of fishers is key to understanding the complex relationship between fisheries and marine mammals, and can help set the basis for management and conservation programs in areas where such interactions are intense. [Display omitted] • The opinions of fishers help to know the relation between fishery and marine mammals. • Common bottlenose dolphin interferes with fishing activities in the coastal zone. • Common bottlenose dolphin fosters a negative perception among fishers. • Spinner and spotted dolphins are reliable indicators of fishing grounds. • Perception of fishes is useful to support management and conservation programs. [ABSTRACT FROM AUTHOR]

Trends in bottlenose dolphin (Tursiops truncatus) strandings can be used to examine several factors associated with mortality and life history and are essential for detecting unusual mortality events (UMEs). This study characterised stranding trends in the Mississippi Sound (MS) region of the northern Gulf of Mexico (GoM) from 1996-2009 using kernel density estimation (KDE) and classification and regression tree (CART) analysis. An annual mean of 26.1 strandings (n = 14), SD = 13.7, 95% CI [18.2, 34.0] and a peak in strandings during spring (March-May) were evident from our analyses. Neonates stranded almost exclusively in spring indicating that this is the dominant breeding and calving season in this area. Spatial distributions revealed that the majority of dolphins stranded along central and western portions of the MS Sound near Gulfport, MS and on Ship Island during the spring and summer months, but were more often found in the eastern MS Sound during winter and autumn. Our CART analyses indicated that 1996, which contained a declared UME, was anomalous from other years as the number of adult, sub-adult and juvenile strandings was relatively high during the autumn and winter. Further, our analyses showed that the location of those strandings on Ship Island in autumn and winter was unique from all other years in the historical record. These results represent historical conditions that can be used as a baseline for future studies of the effects of environmental disturbances, including UMEs, in MS. This research also demonstrates the versatility and usefulness of CART for describing historical trends, detecting departures from the norm and explaining UMEs within the framework of a single analysis. This approach represents an objective assessment tool that could be used to assist governmental agencies with determining the onset of a UME and could help support or refute the cause of these events. [ABSTRACT FROM AUTHOR]

Regional resource limitation in the eastern Levantine Basin was predicted to protract the growth of members of the Israeli sub-population of the common bottlenose dolphin (CBD), compared to CBD sub-populations of similar adult size. Growth curves were fitted to length-at-age data available for 24 male and 26 female CBD stranded or incidentally caught along the Israeli coastline between 2000 and 2009. The obtained model growth constants were compared to those of other CBD sub-populations from the southeastern coast of the United States and a correlation to regional seawater primary productivity was sought. As in other sub-populations, local CBD females initially grow faster than males for approximately 3–4 years and remain longer until around eight years old, after which males surpass them in length. Yet the steep early growth of females as well as its high rate of decay was found to be extreme compared to other CBD sub-populations, with 99% of the asymptotic length being reached at the age of six years. A positive correlation between seawater primary productivity and early growth rate as well as growth decay constants could be demonstrated for CBD males from Texas, Florida and Israeli coasts. Females of the same sub-population presented a non-monotonic relationship to primary productivity. Early female attainment of physical maturity in an ultra-oligotrophic region was unpredicted and is not readily explained. It may accompany early reproductive maturation, selected for as partial compensation for lower lifelong reproductive success. [ABSTRACT FROM PUBLISHER]

Information characterising site fidelity and abundance for common bottlenose dolphins (Tursiops truncatus) along the southwest coast of Florida is important for defining stock structure for management purposes. Long-term site fidelity and ranging patterns of bottlenose dolphins in Charlotte Harbor and Pine Island Sound, Florida were investigated using photo-ID data collected during 566 boat-based surveys from 1982 through 2007. Seasonal abundance estimates were generated from seven multi-week field seasons during 2001 through 2006, before and after a major hurricane and red tide event occurred in the area. In total, 1,154 distinctive dolphins were identified up to 34 times each with 84% of individuals resighted on more than one day. Multiple year residency rates were high with 81% of dolphins sighted in at least two years and 30% over ten or more years. Seventy-six percent of individuals with sightings on two or more days were observed in both summer and winter. Of 249 dolphins sighted on ten or more days in the study area, 83% were never observed outside the study area, indicating strong site-fidelity. Two years after a devastating Category 4 hurricane in 2004 and following two years of Karenia brevis harmful algal blooms, 94% of dolphins were observed in the same region within the study area and abundance estimates remained stable. Documenting range and site fidelity patterns of individuals over long periods of time is helpful for characterizing population structure and for examining changes attributable to environmental factors and perturbations such as hurricanes, harmful algal blooms and climate change. [ABSTRACT FROM AUTHOR]

The article presents a study of the long distance movements in coastal bottlenose dolphins (Tursiops truncatus) in Great Britain and Ireland sites. The study uses photographs of natural markings to examine the potential of common bottlenose dolphins for long distance movements. It reveals evidence for connectivity between areas that have been regarded as discrete. It highlights the need to mitigate broader-scale anthropogenic impacts on dolphins in various sites across their coastal range, as well as the importance of creating wider conservation measures in British and Irish waters.

The article presents a review of conservation and research regarding cetacean in Sri Lanka. It highlights the potential and existing threats on cetacean species and fisheries industries due to increasing shipping traffic, unregulated marine tourism and bycatch in Sri Lankan waters. It considers the impact of resource constraints to the implementation of national legislation and relevant laws for the conservation of cetacean. It notes that insufficient resources to promote long-term research on cetacean have prevailed gaps in conservation knowledge. Moreover, it suggests the use of law enforcement and provision of adequate resources for the development of systematic research on Sri Lanka's cetacean species.

The article discusses a study which examines the genetic differentiation of bottlenose dolphins in two social groups in Biscayne Bay, Florida and between and the adjacent group of dolphins in Florida Bay, Florida. Skin biopsy samples obtained from common bottlenose dolphins using remote biopsy method from May 2002 and April 2003 were genotyped at microsatellite and sequenced for the mitochondrial DNA (mtDNA) control region. The results showed a significant genetic differentiation between the dolphins in Florida Bay and Biscayne Bay.

While bottlenose dolphins in Mediterranean waters often display a high degree of site fidelity, movements across distant areas can occur. Such movements have important implications in terms of population viability, particularly in basins with low bottlenose dolphin densities. We report movements of nine individuals photo-identified up to 265 km apart in western Greece. Four showed a certain degree of site fidelity to one area across several years, but were also found elsewhere, with two individuals moving between two areas. This study provides further evidence that animals appearing to be 'resident' within a given area can temporarily leave and range widely. [ABSTRACT FROM AUTHOR]

Understanding the evolution of brain lateralisation including the origin of human visual laterality requires an understanding of brain lateralisation in related animal species. However, little is known about the visual laterality of marine mammals. To help correct this lack, we evaluated the influence of familiarity with a human on the visual response of five captive bottlenose dolphins. Dolphins gazed longer at unfamiliar than at familiar humans, revealing their capacity to discriminate between these two types of stimuli. Pooled data for responses to all test stimuli demonstrated a preferential use of left eye by all our five dolphin subjects. However, familiarity with particular humans did not influence preferential use of a given eye. Finally, we compared our results with those on other vertebrates. [ABSTRACT FROM AUTHOR]

Odontocete depredation involves stealing or damaging bait or prey already captured by fishing gear. The increase in depredation is of concern for small stocks of cetaceans because interactions with fishing gear can lead to serious injury or mortality through entanglement or ingestion. Using long-term data sets available for the bottlenose dolphin ( Tursiops truncatus) community in Sarasota Bay, Florida, we investigated recreational fishing gear interactions by (1) examining temporal patterns in depredation and associated behaviors from 2000 to 2007; (2) quantifying the behavior of dolphins that depredate or engage in associated behaviors; and (3) identifying factors associated with the rise in depredation locally. The number of incidents of dolphins (primarily adult males) interacting with recreational anglers and boaters increased following 2004. Depredation and associated behaviors increased during red tide lags and tourist seasons during times of prey depletion and heightened angler and boater activity. Dolphins with a history of fishing gear interactions shifted away from natural activity patterns and were more likely to be within 50 m of fishing lines. Recreational fishing gear interactions were attributed to a two percent population decline in Sarasota Bay in 2006 and need to be considered along with other cumulative human impacts in the development of conservation measures for dolphins. [ABSTRACT FROM AUTHOR]

The common bottlenose dolphin (Tursiops truncatus) is a cosmopolitan species that does not range to latitudes greater than 45° in either hemisphere, with a few exceptions. In South American waters, this species is generally distributed in the Atlantic Ocean south to Chubut province (ca. 46° S), while in the eastern South Pacific this species has been recorded in northern and central Chile, with a few records south to 40° S. Here we summarize recent records of common bottlenose dolphins obtained during systematic marine mammal surveys in the Chilean Patagonian and Fuegian channels and fjords (the Los Lagos, Aysén, and Magallanes regions of Chile). These data suggest an extension of the documented range of the species southwards, indicating that bottlenose dolphins may have colonized new areas in the eastern South Pacific or as the result of an increase in survey efforts by scientists in the region. [ABSTRACT FROM AUTHOR]

Bottlenose dolphins are the only cetaceans regularly observed in the northern Adriatic Sea, but they survive at low densities and are exposed to significant threats. This study investigates some of the factors that influence habitat use by the animals in a largely homogeneous environment by combining dolphin data with hydrological and physiographical variables sampled from oceanographic ships. Surveys were conducted year-round between 2003 and 2006, totalling 3,397 km of effort. Habitat modelling based on a binary stepwise logistic regression analysis predicted between 81% and 93% of the cells where animals were present. Seven environmental covariates were important predictors: oxygen saturation, water temperature, density anomaly, gradient of density anomaly, turbidity, distance from the nearest coast and bottom depth. The model selected consistent predictors in spring and summer. However, the relationship (inverse or direct) between each predictor and dolphin presence varied among seasons, and different predictors were selected in fall. This suggests that dolphin distribution changed depending on seasonal forcing. As the study area is relatively uniform in terms of bottom topography, habitat use by the animals seems to depend on complex interactions among hydrological variables, caused primarily by seasonal change and likely to determine shifts in prey distribution. [ABSTRACT FROM AUTHOR]

• Common bottlenose dolphins showed yawn-like behaviors during inactive states. • After yawn-like behavior, inactivity levels decreased in three out of five cases. • Yawn-like behavior is similar to yawning in humans or other terrestrial mammals. • First report of yawning in fully aquatic mammals. • Inhalation and exhalation should be deleted from the definition of animal yawning. Yawning is an involuntary action that begins with a slow opening of the mouth with inhalation, followed by a maximum gaping phase, and ends with a short exhalation and the closing of the mouth. A wide variety of vertebrate species, including humans, yawn. Here, we report underwater yawn-like behavior in three captive common bottlenose dolphins, inferred from 119-h of observations. Five cases of yawn-like behavior were selected out of 2045 open-mouth behaviors, after removing intentional open-mouth behaviors. Yawn-like behaviors were chosen that had a mouth open–close duration ratio of ≤ 1 (duration of Phase 3, the period of mouth closing after maximum opening, divided by the duration of Phase 1, the period of mouth opening from start to maximum opening). Naïve human evaluators selected "yawn-like" behaviors. All five cases of yawn-like behavior occurred during inactive periods, similar to human yawns. In three of the five cases, inactivity levels significantly decreased within 4 min after the yawn-like behavior; therefore, yawn-like behavior in dolphins may increase their arousal level in drowsy states. Thus, the yawn-like behavior of dolphins, without breathing, is similar to yawning in terrestrial animals, including humans. [ABSTRACT FROM AUTHOR]

In this study, Anisakis nematodes isolated from toothed and baleen whales from localities around Japan were molecularly (PCR-RFLP) identified. In Wakayama, common bottlenose dolphins (Tursiops truncatus) were infected with A. simplex sensu stricto (s.s.), A. typica and A. pegreffii , while A. typica was the only species found in pantropical spotted dolphin (Stenella attenuata) and striped dolphin (S. coeruleoalba). Offshore common minke whales (Balaenoptera acutorostrata) and sei whales (B. borealis) were almost exclusively infected with A. simplex s.s.. However, in common minke whales from two Hokkaido localities, mature worms mostly consisted of A. simplex s.s. in some individuals and of A. pegreffii in others, but immature worms were mainly A. simplex s.s.. Gross and histopathological examination on gastric mucosa attached by anisakids resulted in mild and superficial reactions by the two baleen whale species in contrast to severe inflammatory reaction associated with ulcer formations by common bottlenose dolphin. Host specificity and adaptability of Anisakis spp. in these baleen and toothed whales were discussed from the points of view of adult worm size, worm population and pathological reactions by hosts. Interestingly, most of the common minke whales predominantly harboring mature A. pegreffii adults belonged to the Yellow Sea – East China Sea stock (J stock), which migrates through the Sea of Japan, whereas most of those mainly parasitized by mature A. simplex s.s. adults were from the Okhotsk Sea – West Pacific stock (O stock), mostly inhabiting the Pacific side, suggesting that these sibling species may have utility as biological tags to differentiate whale stocks. These results represent the first definitive host records for A. pegreffi in the Northwestern Pacific Ocean. [ABSTRACT FROM AUTHOR]

Background: Common bottlenose dolphins (Tursiops truncatus) are distributed globally in tropical and warm-temperate waters with coastal and offshore ecotypes known. In the eastern North Pacific Ocean, common bottlenose dolphins are typically found in offshore waters as far as 41° N and in coastal waters as far as 38° N. Despite considerable survey effort, the species has not been previously recorded in Canadian Pacific waters. Results: On 29 July 2017, a group of approximately 200 common bottlenose dolphins were observed together with approximately 70 false killer whales (Pseudorca crassidens) in waters of 16.5° C at 50° N during a pelagic seabird and marine mammal survey off the west coast of northern Vancouver Island, British Columbia, Canada. Conclusions: This sighting represents the only occurrence of common bottlenose dolphins recorded in Canadian Pacific waters and, to our knowledge, is the most northerly record for this species in the eastern North Pacific. It is also the first sighting record of false killer whales in non-coastal waters in British Columbia, Canada. The occurrence of both species may be associated with a prolonged period of warming in offshore regions of the eastern North Pacific. [ABSTRACT FROM AUTHOR]

Cetaceans exhibit vaginal folds, unusual protrusions of the vaginal wall into the vaginal lumen. Inconsistent terminology and a lack of anatomical landmarks in the literature have hindered comparative studies of the form and function of vaginal folds. Our objectives are to: (1) develop a standardized measurement protocol for the reproductive tracts of female cetaceans, (2) assess variation in morphometrics within the common bottlenose dolphin (Tursiops truncatus), and (3) determine if vaginal muscle is skeletal, and therefore of somatic origin in this species. We selected 15 measurements to characterize female reproductive tracts and evaluated variability using fresh or frozen-thawed specimens from southeastern USA representing a range of sexual maturity states and reproductive states (n = 18 specimens). Presence of skeletal muscle and variation in the density of muscle banding were assessed using 90 histological samples (n = 5 specimens). Analyses of the gross morphological data revealed that the dolphins generally had one large vaginal fold that bisected the vaginal lumen. Vaginal morphology was similar for sexually mature and immature specimens and across reproductive states. The histological data revealed that the vaginal musculature consisted of smooth muscle, consistent with other mammals, leading us to conclude that vaginal contractions are likely under autonomic rather than somatic control. No differences were found in the density of smooth muscle banding among vaginal regions or sexual maturity states. Our systematic protocol lays the foundation for evaluating the function (e.g., sexual selection, natural selection) and evolution of vaginal folds., (© 2016 Wiley Periodicals, Inc.)