Volume 44 - Issue 4


44.4 Cover FRONT

Abstract: Three wild-caught female harp seals (Pagophilus groenlandicus) from the Greenland Sea stock were brought into temporary captivity in connection with a controlled validation study on energetics. The two pups and one adult were kept in two indoor and outdoor experimental facilities approved by the Norwegian Animal Research Authority. They were trained daily using operant conditioning to participate in experiments and husbandry and were regularly fed live fish. After 2.5 years, the harp seals were instrumented with satellite transmitters and released in the Barents Sea under a Norwegian Food Safety Authority permit. The tags transmitted for 45, 67, and 162 days for the juveniles and adult, respectively. The two juveniles remained in the Barents Sea east of the Svalbard Archipelago, while the adult female migrated to the Greenland Sea following a pattern consistent with that observed in wild harp seals from the same stock. They all performed regular deep dives (>100 m) and exhibited signs of foraging comparable to wild harp seals. Our results suggest that it is possible to conduct temporary captive studies with wild juvenile and adult harp seals. Study animals can be trained and subsequently released if they meet a set of criteria. This framework combines advantages of captive study design with traditional field methods and follows European ethical guidelines on animal experimentation with respect to the re-homing of experimen¬tation animals.
Key Words: temporary captivity, satellite telemetry, release, rehabilitation, harp seal, Pagophilus groenlandicus
Document: Article
DOI: https://doi.org/10.1578/AM.44.4.2018.343
Page Numbers: 343-356

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Document: Short Note
DOI: https://doi.org/10.1578/AM.44.4.2018.357
Page Numbers: 357-366

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Abstract: The objective of this study was to test the potential influence of short-term changes in water quality on the frequency of sightings of common dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida. The study was based on two data sources: (1) Land/Ocean Biogeochemical Observatories (LOBOs) that provided real-time monitoring of multiple water quality and weather parameters, and (2) standardized methods for identifying and counting individual dolphins using photo-identification techniques. Water quality parameters included salinity, water color (chromophoric dissolved organic matter), conductivity, dissolved oxygen concentration, oxygen saturation, chlorophyll, nitrate and phosphate concentrations, temperature, and turbidity. Weather was assessed using data for air temperature, barometric pressure, humidity, light, and wind speed and direction. Variables were measured continuously over a one-year period and analyzed as the mean for each parameter the hour before, during, and after each dolphin sighting period. Short-term variations in sightings within 0.5 km of the LOBO were measured using previously established photo-identification techniques on a weekly basis. In multivariable regression analyses, statistically significant inverse associations were found between air temperature and the frequency of dolphin sightings for all three time periods. The results demonstrate the feasibility of integrating variation in weather and water chemistry data with dolphin movements as potential indicators of ecosystem quality and climate change.
Key Words: common bottlenose dolphins, Tursiops truncatus, water quality, photo-identification, Land/Ocean Biogeochemical Observatories, weather, Indian River Lagoon
Document: Article
DOI: https://doi.org/10.1578/AM.44.4.2018.367
Page Numbers: 367-373

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Abstract: Determining the trophic position and trophic width of animals within food webs is essential to defining their ecological role. California sea lions (CSLs; Zalophus californianus) are widely distributed along the dynamic coast of the northeast Pacific; thus, their diet is shaped by the unique setting and environmental conditions of each colony. Our goal was to determine the trophic position and isotopic niche of CSLs from two colonies in Mexico in distinct environments (Gulf of California vs west coast of the Baja California peninsula) by examining the carbon and nitrogen isotopic signatures in vibrissae. The Gulf of California is a marginal sea where primary productivity is based on seasonal upwelling and intense tidal mixing. In contrast, primary productivity on the west coast of the Baja California peninsula depends on seasonal upwelling as well as the productive California Current System. One mystacial vibrissa was removed from each CSL captured on San Esteban Island (SEI) (N = 10) in the Gulf of California during the 2011 breeding season, and on Santa Margarita Island (SMI) (N = 16) on the Pacific coast of the Baja California peninsula during the 2012-2013 breeding season. Bayesian techniques were used to determine the trophic niche and trophic position. The trophic niche was wider at SMI than at SEI as more habitats are available to female CSLs at the former (e.g., coastal, pelagic, and lagoonal). However, despite the wider trophic niche and array of habitat types, the trophic level was the same for both colonies, suggesting that CSLs may maintain their trophic position across variable ecosystems. The accurate evaluation of the geographic variation in the trophic position of female CSLs allows us to better understand how these marine mammals utilize the distinct resources available in the habitats they occupy.
Key Words: Gulf of California, stable isotopes, isotopic niche, vibrissae, San Esteban Island, Santa Margarita Island, foraging, pinniped
Document: Article
DOI: https://doi.org/10.1578/AM.44.4.2018.374
Page Numbers: 374-388

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Abstract: Naval sonar signals may affect the behavior of harbor porpoises (Phocoena phocoena). The 53C sonar system produces 1,600 ms sonar signals in the 3.5 to 4.1 kHz band, each consisting of a sweep immediately followed by two tones which are separated by a 100 ms silence. Effects of sound pressure level (SPL) and duty cycle on the behavioral responses of two harbor porpoises to these sounds were investigated. Respiration rate, distance to the transducer, swimming speed, and the number of jumps during sound exposure and baseline periods were compared. Harbor porpoises were exposed to 30-min playbacks of 53C sonar sounds at five average received SPLs (Lrecs) with a duty cycle of 2.7%, and at six Lrecs with a duty cycle of 96%, under low ambient noise conditions. They did not respond to the sounds when the duty cycle was 2.7%, even at the maximum Lrec (143 dB re 1 μPa). When the duty cycle was 96%, only Porpoise 06 increased his respiration rate when the Lrec was ≥119 dB re 1 μPa, and he moved away from the transducer only at an Lrec of 143 dB re 1 μPa. At the same Lrec and duty cycle, the effect of 53C sonar sounds on harbor porpoise behavior was weaker than that of 1 to 2 kHz, 6 to 7 kHz, and 25 kHz sonar signals observed in previous studies.
Key Words: avoidance, behavior, duty cycle, naval sonar, odontocete, respiration rate, response
Document: Article
DOI: https://doi.org/10.1578/AM.44.4.2018.389
Page Numbers: 389-404

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Abstract: The goal of this study was to test transthoracic echocardiography as a method to characterize heart morphology and function in the southern sea lion (SSL) (Otaria flavescens) for health evaluation. Four clinically healthy captive SSLs (mean weight 110 ± 17.5 kg) were trained to be examined by transthoracic echocardiography at Mar del Plata Aquarium in Mar del Plata, Argentina. Two-dimensional guided M-mode images were obtained using a portable cardiovascular ultrasound system equipped with a 1.5 to 3.5 MHz convex 3S phased-array transducer. The mean left ventricular internal dimension at end-diastole was 73 ± 5.8 mm; the mean interventricular septum thickness and posterior wall thickness at end-diastole were 9 ± 1.1 mm and 8.9 ± 2 mm, respectively. Fractional shortening and ejection fraction were 44.6 ± 1.7% and 74.4 ± 1.7%, respectively. The left atrial diameter-to-aortic root index was 0.92 ± 0.03. The most suitable position for obtaining good quality images was the left lateral recumbency (with slight inclination to 45°), with the probe placed on the left side of the thorax, ventrally just near the sternum, at the level of the caudal portion of the left pectoral fin. The best acoustic window in relation to the breathing cycle occurred between the end of the expiration and the beginning of the next inspiration. We successfully demonstrated that the in vivo structure and function of the SSL heart can be safely and effectively evaluated by transthoracic echocardiography in captive trained animals. These data have clinical and research implications for evaluating diseases of the cardiopulmonary system in pinnipeds.
Key Words: echocardiography, trained behavior, pinnipeds, heart anatomy, heart disease
Document: Article
DOI: https://doi.org/10.1578/AM.44.4.2018.405
Page Numbers: 405-410

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Abstract: A booming whale-watching industry in Juneau, Alaska, is raising concerns over potential impacts to humpback whales (Megaptera novaeangliae) and the sustainability of this growing industry. In this study, we investigated the physiological response of these whales to chronic vessel disturbance by measuring hormone concentrations (cortisol, progesterone, testosterone, and estradiol) that have been sequestered in blubber throughout the whale-watching season. We focused our analysis on cortisol, a steroid hormone associated with stress response, and hypothesized that cortisol in biopsy samples would be positively correlated with the amount of vessel traffic in the 3 to 4 months prior to sampling. Humpback whales in the Juneau area were compared with whales from control areas with far less vessel traffic in both Southeast Alaska and the western Gulf of Alaska using biopsies collected late in the tour season. We did not find elevated cortisol in whales sampled in the Juneau area relative to the Southeast Alaska control area (p = 0.14) or sites in the western Gulf of Alaska, which had higher cortisol levels (p < 0.001). The cause of the regional cortisol differences is not known but could be rep¬resentative of regional differences in baseline hormone concentrations or be linked to predator or nutritional stressors. The lack of elevated cortisol in Juneau-area whales suggests high vessel traffic is not resulting in chronic cortisol sequestration in whales and may be indicative of whales near Juneau being habituated to vessel traffic.
Key Words: cortisol, blubber, humpback whale, Megaptera novaeangliae, whale watching, stress response, ecotourism
Document: Article
DOI: https://doi.org/10.1578/AM.44.4.2018.411
Page Numbers: 411-425

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Abstract: Dolphin cognitive abilities have been examined by establishing a concept-oriented cue, the innovate discriminative stimulus (SD), wherein an individual is required to perform something new or different upon each stimulus given. Although a number of facilities have trained this behavior with a wide range of species, neither the training nor the level of creativity in response to this cue has been researched systematically. Moreover, differing criteria exist for whether novel or different behaviors should be defined as innovative as evidenced by the research to date. Ultimately, our goal is to establish a research and training protocol for using the innovate SD to assess the creative abilities in nonhuman species. We compared innovate training methodologies used with dolphins specifically, although a number of other species have been trained on this behavior based on anecdotal reports. Our literature review, including discussions with trainers, indicated that a number of potential pitfalls occur when training this cognitive task (e.g., avoid shaping a chained behavioral response). This methodological review provides both a clear definition of the criteria accepted for innovative behavior and a suggested approach for training and testing this concept in dolphins. Finally, the more unambiguously that we understand innovative behavior in a controlled setting, such as under stimulus control, the more we will be able to gain from studies of spontaneous behavior and other examples of behavioral innovation observed in the wild.
Key Words: innovative, creative, cognition, training approach, bottlenose dolphins, Tursiops truncatus
Document: Article
DOI: https://doi.org/10.1578/AM.44.4.2018.426
Page Numbers: 426-436

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Document: Historical Perspectives essay
DOI: https://doi.org/10.1578/AM.44.4.2018.437
Page Numbers: 437-457

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