Institute for Marine Mammal Studies

The age of an individual is an essential demographic parameter but is difficult to estimate without long‐term monitoring or invasive sampling. Epigenetic approaches are increasingly used to age organisms, including nonmodel organisms such as cetaceans. Māui dolphins (Cephalorhynchus hectori maui) are a critically endangered subspecies endemic to Aotearoa New Zealand, and the age structure of this population is important for informing conservation. Here we present an epigenetic clock for aging Māui and Hector's dolphins (C. h. hectori) developed from methylation data using DNA from tooth aged individuals (n = 48). Based on this training data set, the optimal model required only eight methylation sites, provided an age correlation of .95, and had a median absolute age error of 1.54 years. A leave‐one‐out cross‐validation analysis with the same parameters resulted in an age correlation of .87 and median absolute age error of 2.09 years. To improve age estimation, we included previously published beluga whale (Delphinapterus leucas) data to develop a joint beluga/dolphin clock, resulting in a clock with comparable performance and improved estimation of older individuals. Application of the models to DNA from skin biopsy samples of living Māui dolphins revealed a shift from a median age of 8–9 years to a younger population aged 7–8 years 10 years later. These models could be applied to other dolphin species and demonstrate the ability to construct a clock even when the number of known age samples is limited, removing this impediment to estimating demographic parameters vital to the conservation of critically endangered species.

Abstract Although Hubbs' beaked whale (Mesoplodon carlhubbsi) was previously known from over 60 strandings on both sides of the North Pacific, it had been identified alive in the wild only once, off Oregon in 1994. In September 2021, we conducted a search effort for beaked whales off the coast of Oregon using a towed hydrophone array and a visual search team. Approximately 350 km off the Columbia River mouth, we detected the vocalizations of an unidentified mesoplodont whale; we stopped our vessel and waited in the area until two unidentified juvenile Mesoplodon surfaced and stayed near our vessel for almost 2 hr. During that time, we took numerous photographs and videos, made behavioral observations, and recorded their vocalizations. The DNA sequence from a biopsy sample identified them as M. carlhubbsi. In this paper, we discuss our biological observations, including color patterning and acquired markings, behavioral observations, and describe for the first time the acoustic characteristics of this species. We confirm that M. carlhubbsi is the source of a previously unidentified acoustic signal known as BW37V, and we update what is known about the at‐sea distribution of this species based on previous recordings and observational records.

The aim of this study was to compare the effect of different types of instructional styles-traditional lecture with and without video examples and contemporary format that simulated a flipped classroom-on dental students' learning of behavior guidance techniques (BGTs) in pediatric dentistry. The study also sought to determine if students had an improved comfort level with BGTs with these instructional methods, if videos improved learning and comfort with BGTs, and if there were differences in outcomes by gender. All 96 second-year dental students at one U.S. dental school were recruited to participate in the study in 2017. Students were randomly divided into three groups: contemporary instruction (CI), traditional instruction with video (TIV), and traditional instruction with no video (TI). CI students watched a 20-minute mini-lecture and were divided into discussion groups led by calibrated faculty members. TIV students received 50 minutes of traditional lecture with video examples. TI students received a traditional lecture with no video examples. All groups completed a questionnaire prior to and on completion of the course. The questionnaire assessed students' learning and perceptions of the learning experience. All students participated in the course and the assessments, for a 100% response rate. The students' post-course scores improved for all teaching methods (TI>CI>TIV) with no significant differences among them. CI students rated comfort with BGTs and usefulness of videos higher than the other groups, but the difference was not statistically significant. Students rated their satisfaction with and usefulness of the course high for all groups (>3 on a four-point scale). Learning style and comfort treating children were not statistically significant by gender. Overall, the students reported high satisfaction with all the teaching methods. Although the differences were not statistically significant, discussion groups were ranked highest in satisfaction and usefulness.

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

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Summary Management of highly migratory species is reliant on spatially and temporally explicit information on their distribution and abundance. Satellite telemetry provides time‐series data on individual movements. However, these data are underutilized in management applications in part because they provide presence‐only information rather than abundance information such as density. Eastern North Pacific blue whales are listed as threatened, and ship strikes have been suggested as a key factor limiting their recovery. Here, we developed a satellite‐telemetry‐based habitat model in a case–control design for Eastern North Pacific blue whales Balaenoptera musculus that was combined with previously published abundance estimates to predict habitat preference and densities. Further, we operationalize an automated, near‐real‐time whale density prediction tool based on up‐to‐date environmental data for use by managers and other stakeholders. A switching state‐space movement model was applied to 104 blue whale satellite tracks from 1994 to 2008 to account for errors in the location estimates and provide daily positions (case points). We simulated positions using a correlated random walk model (control points) and sampled the environment at each case and control point. Generalized additive mixed models and boosted regression trees were applied to determine the probability of occurrence based on environmental covariates. Models were used to predict 8‐day and monthly resolution, year‐round density estimates scaled by population abundance estimates that provide a critical tool for understanding seasonal and interannual changes in habitat use. The telemetry‐based habitat model predicted known blue whale hot spots and had seasonal agreement with sightings data, highlighting the skill of the model for predicting blue whale habitat preference and density. We identified high interannual variability in occurrence emphasizing the benefit of dynamic models compared to multiyear averages. Synthesis and applications. This near‐real‐time tool allows a more accurate examination of the year‐round spatio‐temporal overlap of blue whales with potentially harmful human activities, such as shipping. This approach should also be applicable to other species for which sufficient telemetry data are available. The dynamic predictive product developed here is an important tool that allows managers to consider finer‐scale management areas that are more economically feasible and socially acceptable.

In the wild, California sea lions (Zalophus californianus) are exposed to a wide variety of sensory information, which cannot be replicated in captive environments. Therefore, unique procedures are necessary for maintaining physiological and psychological health in nonhuman animals in captivity. The effects of introducing natural scents to captive enclosures have been investigated in a variety of species, yet they have not been examined in marine mammals. This project explored the behavioral effect of scent added to the environment, with the goal of improving the welfare of sea lions in captivity. Two scent types were introduced: (a) natural scents, found in their native environment, and (b) non-natural scents, not found in their native environment. This study examined not only scent enrichment but also the possible evolutionary underpinnings of pinniped olfaction. Scent enrichment was found to significantly impact sea lion behavior as demonstrated by a reduction in pattern swimming, an increase in habitat utilization, and a reduction in stereotypical behavior. However, there were no differences in behavior between natural and non-natural scent conditions.

A northern Gulf of Mexico (GoM) cetacean unusual mortality event (UME) involving primarily bottlenose dolphins (Tursiops truncatus) in Louisiana, Mississippi, and Alabama began in February 2010 and continued into 2014. Overlapping in time and space with this UME was the Deepwater Horizon (DWH) oil spill, which was proposed as a contributing cause of adrenal disease, lung disease, and poor health in live dolphins examined during 2011 in Barataria Bay, Louisiana. To assess potential contributing factors and causes of deaths for stranded UME dolphins from June 2010 through December 2012, lung and adrenal gland tissues were histologically evaluated from 46 fresh dead non-perinatal carcasses that stranded in Louisiana (including 22 from Barataria Bay), Mississippi, and Alabama. UME dolphins were tested for evidence of biotoxicosis, morbillivirus infection, and brucellosis. Results were compared to up to 106 fresh dead stranded dolphins from outside the UME area or prior to the DWH spill. UME dolphins were more likely to have primary bacterial pneumonia (22% compared to 2% in non-UME dolphins, P = .003) and thin adrenal cortices (33% compared to 7% in non-UME dolphins, P = .003). In 70% of UME dolphins with primary bacterial pneumonia, the condition either caused or contributed significantly to death. Brucellosis and morbillivirus infections were detected in 7% and 11% of UME dolphins, respectively, and biotoxin levels were low or below the detection limit, indicating that these were not primary causes of the current UME. The rare, life-threatening, and chronic adrenal gland and lung diseases identified in stranded UME dolphins are consistent with exposure to petroleum compounds as seen in other mammals. Exposure of dolphins to elevated petroleum compounds present in coastal GoM waters during and after the DWH oil spill is proposed as a cause of adrenal and lung disease and as a contributor to increased dolphin deaths.