Citizen science projects are an advantageous method to carry out research in the marine environmental field, especially concerning high mobile and often elusive species like cetaceans, allowing the ...collection of data in wide spatial-temporal scale. This project aims to validate the feasibility and accuracy of cetacean monitoring program through the citizen science approach and to test the efficiency of this method to large scale study area. In this work data obtained by researchers monitoring were compared with data coming from citizen, which followed specifically developed protocol. Data collected were used to investigate the presence and distribution of bottlenose dolphins (Tursiops truncatus) in the Sicilian Channel and to evaluate the contribution of citizen scientist to improve knowledge about species, in this case for bottlenose dolphin a vulnerable species listed in the Annex II of Habitat Directive (92/43 CE). The results show that citizen dataset contributes to increase the distribution map of the 22% more than only research data were considered. Citizen science programme results useful to gain information in small areas not monitored by scientific programs, such as in this study, and they would be very useful if applied at large-scale. The promotion of citizen science programs in specified small areas could be helpful to cover unmonitored zones, to gain preliminary results and bridge the gap of knowledge about species occurrence and distribution. For this reason, citizen support might help competent authorities to answer to the environmental policies as Habitat Directive and Marine Strategy Framework Directive. This study is a demonstration of how citizen can encourage scientists to start long-term research project in not regularly monitored areas.
•18 cetacean sightings were reported by citizen and 7 by research monitoring.•Recreational fishermen and pleasure boaters were the most participative.•Research dataset results in 1 dolphin core-area of 356 km 2 at 30–40 m depths.•Citizen dataset results in 3 dolphin core-areas of 98 km 2 inshore, at 20 m depths.•Citizen contributes to increase knowledge on dolphin distribution of the 22%.
Coastal waters of the Valencia region are important habitats for bottlenose dolphins, but also important fishing grounds for artisanal fisheries. No studies have been carried out here to investigate ...the overlap and interactions between the fishing grounds and dolphin habitat. The present study aims to assess the potential occurrence of interactions between artisanal fisheries and bottlenose dolphins in these waters. Face to face interviews were conducted to investigate for the first time artisanal fishermen's perceptions of their interactions with bottlenose dolphins.
A total of 131 fishermen (40.1% of the artisanal fleet for the Valencia region) participated of research. Among the interviewed fishermen, 86.1% perceived that dolphins damaged fishing gear as they attempted to feed, and they also detected significant direct damage to fish. Of all fishermen reporting a negative interaction with bottlenose dolphins, 76.3% also reported financial loss (2907.1 ± 2512.7 €/year (100–12,000). Despite the high level of interaction with dolphins reported, fishermen do not consider bycatch to be an important threat for bottlenose dolphins. Our results show geographical differences in fishermen's perceptions of damage caused by dolphins: while dolphins were considered to be the second cause of economic loss in the southernmost ports, fishermen from the northern ports considered interaction with bottom trawl boats to be more harmful than interaction with dolphins. The more intense interaction reported by fishermen in fishing ports in the southern study area may be associated with higher presence of bottlenose dolphin in these zones. Our study provides a useful insight into fishermen's perceptions of interaction between bottlenose dolphins and artisanal fisheries in this key area for the species in the western Mediterranean Sea. It also highlights the need for future work including direct observations of interactions and damage to gather reliable data to assess the need for conservation measures.
•Artisanal fisheries fishing grounds and bottlenose dolphin habitat overlap in Valencia region.•Fishermen claim that dolphins cause damage that entails economic loss.•Fishermen does not perceive bycatch as a negative aspect of fisheries on bottlenose dolphin.•Differences in interaction perception among ports seems related to dolphin distribution.•Future direct measures are necessary to validate fishermen perceptions previous to any management implementation.
Investigating resource partitioning among mobile marine predators such as cetaceans is challenging. Here we integrate multiple methodologies (analyses of habitat use, stable isotopes and trace ...elements) to assess ecological niche partitioning amongst two genetically divergent sympatric subpopulations (North and South) of Indo‐Pacific bottlenose dolphins (Tursiops aduncus) in Moreton Bay, Australia. Comparisons of the mean locations (latitude, longitude) and environmental variables (distance from sandbanks, distance from shore and water depth) observed at sightings of biopsy‐sampled individuals indicated that the North subpopulation occurred in the northwestern bay in significantly deeper water than the South subpopulation, which was found in southeastern nearshore waters and closer to sandbanks. Ratios of stable carbon and nitrogen isotopes in skin samples suggested that North dolphins foraged on higher trophic level prey in relatively more pelagic, offshore habitats, while South dolphins foraged on lower trophic prey in more nearshore, demersal and/or benthic habitats. Habitat partitioning was also reflected in higher blubber concentrations of most of the 13 measured trace elements, in particular lead, in the coastal South compared to the more pelagic North dolphins. These findings indicate that genetic subpopulations of bottlenose dolphins in Moreton Bay are adapted to different niches.
Pulmonary mycosis is a fungal disease that commonly affects bottlenose dolphins (Tursiops truncatus) and is generally treated by the oral administration of azoles, such as itraconazole (ITZ) and ...voriconazole (VRZ). However, antifungal susceptibility testing of clinical isolates has not been well performed as a routine clinical examination in aquaria. In this study, we collected fungal species from the blowholes of 14 bottlenose dolphins, of which 12 were treated with ITZ or VRZ. All dolphins were housed in the Port of Nagoya Public Aquarium. The fungal species Candida albicans, C. tropicalis, C. glabrata, Aspergillus fumigatus, and A. niger were isolated. E-tests were performed to determine the minimum inhibitory concentrations (MICs) of ITZ and VRZ on these isolates. VRZ-resistant C. tropicalis (MIC: >32 μg/ml) and A. niger (MIC: >32 μg/ml) were isolated from three dolphins treated with ITZ or VRZ. Additionally, azole-resistant isolates of C. albicans and C. glabrata were collected from two dolphins that had never received azole therapy. To the best of our knowledge, our study is the first to report the isolation of VRZ-resistant C. albicans, C. tropicalis, and A. niger from the blowholes of bottlenose dolphins. Thus, antifungal susceptibility testing is a crucial strategy for selecting antifungal agents to treat respiratory fungal infections in bottlenose dolphins in aquaria.
A bottlenose dolphin (Tursiops truncatus) housed in the Port of Nagoya Public Aquarium (PNPA) presented with symptomatic pneumonia caused by Aspergillus fumigatus. The dolphin was treated with ...micafungin. On days 2 and 11 after the first administration of micafungin, results from a physical examination and laboratory test indicated a decline of body temperature (BT) and leukopenia, with lowest BT, white blood cells (WBCs), and segmented neutrophils (SEGs) of 34.2ºC, 600 cells/μl, and 67 cells/μl, respectively. BT, WBCs, and SEGs returned to normal range after administration of granulocyte colony stimulating factor (G-CSF). To the best of our knowledge, this is the first report of micafungin-induced decline of BT and leukopenia that was successfully treated with G-CSF in a bottlenose dolphin.
On the captive breeding program of dolphins, it is especially important to have accurate estimation on the calving date as a part of preparation and prevention of accident during giving birth. ...Decline in body temperature is a known sign of prior to parturition therefore many facilities use this as an indicator to determine the date of calving. However, there have been a few reports that female gave birth without showing body temperature decrease. In this study, we analyzed both intermammary cleft width and body temperature changes that recorded in four cases of the birth events at our facility. The results showed that the body temperature significantly decreased one day before delivery, and the intermammary cleft width significantly increased two days before delivery. This result suggests that monitoring both intermammary cleft width and body temperature may allow earlier determination as well as accurate estimation of the date of delivery than temperature measurement alone.
Individually distinctive signature whistles are used by common bottlenose dolphins (Tursiops truncatus) during social interactions and to facilitate group cohesion. There is evidence from a few ...populations that Indian Ocean bottlenose dolphins (T. aduncus) also use signature whistles. We investigated this from a coastal resident population of T. aduncus in Mozambique. Video-audio data were collected during recreational swim-with activities over 12 years, where potential signature whistles were identified from 28 individuals. Of the 405 whistles documented, 75% were produced in SIGID bouts. Visual assessment of individual signature whistle contours demonstrated temporal stability for up to 8 years. Overall, most signature whistle types had upsweep frequency modulation and were emitted as multiloop whistles. Comparing all whistle contours to each other indicated low discrimination between individuals, with contours frequently categorised together. However, sex differences in the frequency characteristics of whistles were identified, with females whistling at lower frequencies than males. Our results indicate either a shared whistle repertoire or identity encoding with subtle contour features, requiring acute auditory perception and discrimination to decipher caller identity. More widespread geographic investigation into signature whistle use may demonstrate variation in acoustic communication systems for bottlenose dolphins, which are thus far not well understood.
Stress hormones, released into circulation as a consequence of disturbance, are classically assayed from blood samples but may also be detected in a variety of matrices. Blubber and fecal samples can ...be remotely collected from free‐ranging cetaceans without the confounding hormone elevations associated with chase, capture, and handling required to collect blood samples. The relationship between cortisol concentrations in circulation with that of blubber and feces, however, is unknown. To assess these associations, we elevated cortisol by orally administering hydrocortisone for five days in five bottlenose dolphins. Voluntary blood and fecal samples were collected daily; blubber biopsies were collected on day one, just prior to hydrocortisone administration, and days three and five of hydrocortisone administration. We evaluated subsequent changes in several circulating stress hormones as well as cortisol and glucocorticoid metabolites in blubber and feces, respectively. There was a significant association between cortisol levels in serum and in blubber (F1,12.7 = 14.3, P < 0.01, mR2 = 0.57) despite substantial variability in blubber cortisol levels. Counterintuitively, fecal cortisol metabolite levels were inversely related to serum cortisol. The relationship between serum and blubber cortisol levels suggests blubber samples from remote sampling may be useful to detect stress loads in this species.
Common bottlenose dolphins (Tursiops truncatus) use individually distinctive signature whistles which are highly stereotyped and function as contact calls. Here we investigate whether Indo‐Pacific ...bottlenose dolphins (T. aduncus) use signature whistles. The frequency trace of whistle contours recorded from three genetically distinct free‐ranging populations was extracted and sorted into whistle types of similar shape using automated categorization. A signature whistle identification method based on the temporal patterns in signature whistle sequences of T. truncatus was used to identify signature whistle types (SWTs). We then compared the degree of variability in SWTs for several whistle parameters to determine which parameters are likely to encode identity information. Additional recordings from two temporarily isolated T. aduncus made during natural entrapment events in 2008 and 2009 were analyzed for the occurrence of SWTs. All populations were found to produce SWTs; 34 SWTs were identified from recordings of free‐ranging T. aduncus and one SWT was prevalent in each recording of the two temporarily isolated individuals. Of the parameters considered, mean frequency and maximum frequency were the least variable and therefore most likely to reflect identity information encoded in frequency modulation patterns. Our results suggest that signature whistles are commonly used by T. aduncus.
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