Aspergillosis is a fungal infection with high mortality and morbidity rates. As in humans, its definitive diagnosis is difficult in animals, and thus new laboratory tools are required to overcome the diagnostic limitations due to low specificity and lack of standardization. In this study of common bottlenose dolphins (Tursiops truncatus), we evaluated the diagnostic performance of a new commercial immunoblot kit that had been initially developed for the serologic diagnosis of chronic aspergillosis in humans. Using this in a quantitative approach, we first established its positive cutoff within an observation cohort of 32 serum samples from dolphins with "proven" or "probable" diagnosis of aspergillosis and 55 negative controls. A novel enzyme-linked immunosorbent assay (ELISA) test was also developed for detecting anti-Aspergillus antibodies, and results were compared between the two assays. Overall, the diagnostic performance of immunoblot and ELISA were strongly correlated (P < .0001). The former showed lower sensitivity (65.6% versus 90.6%), but higher specificity (92.7% vs. 69.1%), with no cross-reaction with other fungal infections caused by miscellaneous non-Aspergillus genera. When assessing their use in a validation cohort, the immunoblot kit and the ELISA enabled positive diagnosis before mycological cultures in 42.9% and 33.3% subjects addressed for suspicion of aspergillosis, respectively. There was also significant impact of antifungal treatment on the results of the two tests (P < .05). In all, these new serological methods show promise in aiding in the diagnosis of aspergillosis in dolphins, and illustrate the opportunity to adapt commercial reagents directed for human diagnostics to detect similar changes in other animals.
Bottlenose dolphins (Tursiops truncatus) rely on sound for communication, navigation, and foraging. Both natural and anthropogenic noise in the marine environment could mask the ability of wild dolphins to detect sounds, and chronic noise exposure could cause permanent hearing loss. The hearing abilities of a wild population of bottlenose dolphins in Sarasota Bay, FL are being investigated to determine whether they suffer hearing losses in comparison to animals living in quieter environments. This study is the first to measure the hearing sensitivity of a large population of wild dolphins that are exposed to significant levels of noise. Data on hearing sensitivities at frequencies used for acoustic communication (5–20 kHz) and echolocation (20–100 kHz) are reported. Hearing sensitivity was measured in the field using the non-invasive auditory brainstem response (ABR) procedure. ABR responses were evoked by the presentation of amplitude-modulated (AM) tones (carrier frequencies of 5, 10, 20, 30, 60, and 80 kHz) through a jawphone. The tones were modulated at 600 Hz, which elicited a robust envelope following response. A rapid ABR procedure was employed so that an entire audiogram could be obtained in approximately 30 min. This study also provides baseline data for longitudinal hearing studies in known individuals.
Stomach contents of a resident community of bottlenose dolphins ( Tursiops truncatus ) from the Sarasota Bay area of the westcentral coast of Florida were studied to examine potential factors leading to patterns of habitat use. Composition and size of prey were analyzed and correlated with feeding behavior of individual dolphins of known histories. Examination of stomach contents of 16 stranded dolphins revealed a diet composed exclusively of fish (蠅15 species), most of which were associated with seagrasses in varying degrees. Observational records for 蠄21 years showed that feeding typically occurred in shallow (2–3 m) waters and in the vicinity of seagrasses in 23% of cases. Dolphins usually fed alone or in small groups and on non-obligate schooling prey. The main species of prey were soniferous, an indication that passive listening may be important in detection of prey. The close agreement between species of fishes represented in stomach contents and habitat of prey, as indicated by observations of feeding, suggests that analysis of stomach contents is a reasonable approach for studying prey and feeding patterns of dolphins. Meadows of seagrass are one of the habitats of importance to dolphins in the Sarasota Bay area, and their protection is important for conservation of these animals.
During the COVID-19 pandemic, changes in vessel activity and associated noise have been reported globally. Sarasota Bay is home to a large and increasing number of recreational vessels as well as a long-term resident community of bottlenose dolphins, Tursiops truncatus. Data were analyzed from two hydrophones to compare the soundscape during the COVID-19 pandemic to previous years (March–May 2020 and 2018/2019). Hourly metrics were calculated: vessel passes, 95th percentile sound levels [125 Hz and 16 kHz third octave bands (TOBs), and two broader bands: 88–1122 Hz and 1781–17 959 Hz], and dolphin whistle detection to understand changes in vessel activity and the effect on wildlife. Vessel activity increased during COVID-19 restrictions by almost 80% at one site and remained the same at the other site. Of the four sound level measures, only the 125 Hz TOB and 88–1122 Hz band increased with vessel activity at both sites, suggesting that these may be appropriate measures of noise from rapid pass-bys of small vessels in very shallow (<10 m) habitats. Dolphin whistle detection decreased during COVID-19 restrictions at one site but remained the same at the site that experienced increased vessel activity. The results suggest that pandemic effects on wildlife should not be viewed as homogeneous globally.
Abstract Hematology, serum chemistry, and plasma hormones were evaluated in 72 pantropical spotted dolphins ( Stenella attenuata attenuata ) from the eastern tropical Pacific in an attempt to define the degree of stress associated with chase and encirclement by a tuna purse seiner, and are here reported for the first time for this species. Dolphins had high levels of dopamine and moderately elevated levels of enzymes indicative of the expected muscle damage following exertion of the chase. The length of time between the start of the capture operation and blood sampling correlated with increases in platelet and white blood cell counts and mean cell hemoglobin concentration, while the length of time between net tie‐down and blood sampling influenced platelet, white blood cell, and eosinophil counts. Ten dolphins recaptured 1–3 d after their first capture had significantly lower serum creatinine kinase, thyroid (T4) and globulin levels compared to values in dolphins sampled at nominal first capture. Although small sample sizes and large individual variation limit interpretation, these data indicate a stress response occurred in all dolphins, but the extent of the response is within the expected range for adaptive responses previously measured in limited numbers of wild mammals.
The analysis of ranging patterns is important to the understanding of species ecology, population dynamics and social and genetic structure. Ranging patterns are influenced by social systems, predation risk, foraging strategies and resource availability. Bottlenose dolphins display a high degree of variability in population structure among different geographic locations. In this study, we investigated differences in ranging patterns between adult male and female Indo-Pacific bottlenose dolphins (Tursiops aduncus) in a temperate environment in Bunbury, Western Australia. To achieve this, we conducted systematic boat-based surveys (n>530) along pre-determined transect lines throughout the 540 km2 study area. Photo-identification data were collected year-round over six consecutive years (2007-2013). More than 1280 dolphin groups were encountered, where over 440 dolphins were catalogued by distinctive fin markings and sex was determined for 55 males and 140 females through genetic analysis or visual observations. A sensitivity analysis was carried out to determine the minimum number of sightings required to most accurately portray range size. Results from minimum convex polygons and fixed kernel estimators revealed that adult males had larger ranges than females and several key areas for females were highlighted. We hypothesize that adult males range further in search for potential mates and that female range patterns are affected by ecological parameters, such as, availability of resources and protection from predators. The key areas identified may be of interest for conservation and management purposes.
The approach selected for the low-level monitoring of Tampa Bay dolphins was photographic identification (photo-ID) surveys from small boats (see reviews by Wursig and Jefferson 1990; Scott et al. 1990a).This technique has proven effective in long-term studies of population-rate parameters in Sarasota Bay, immediately to the south (Wells and Scott 1990).The large numbers of distinctive dolphins photographed by Wells (1986) during surveys initiated in 1975, and later by Weigle (1990) indicated that Tampa Bay would be an excellent case study for photo-ID surveys.Photo-ID offers several advantages over aerial surveys for measuring certain population rate parameters.The greatest advantage of using photo-ID methods is the accumulation of information on the occurrence, distribution, and ranging patterns of specific individuals.The ability to recognize individuals over time provides opportunities to estimate abundance using mark-resight methods, to evaluate possible cases of immigration, emigration, or transience, to monitor individual female reproductive case histories, to determine the origins of carcasses for mortality estimates, and to examine community structure (Wells 1986).
There are many reports of cetaceans with deformed and twisted bodies. Skeletal pathology descriptions have shown changes to axial skeletons because of injury, trauma, or disease. We present a bottlenose dolphin (Tursiops truncatus) that shows characteristic patterns of congenital skeletal deformity, including malformed vertebrae, ribs, and sternum. These malformations were consistent with segmentation and formation defects arising during early embryonic development, with a resulting cascade of deformity and compensatory pathology. In spite of severe deformities, the dolphin lived 18 yr, raised two calves, and likely would have lived longer had she not succumbed to sepsis and the piercing of the aorta caused by a stingray barb.
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