There is increasing evidence that whale and dolphin watching activities have detrimental effects on targeted cetacean populations. In Egypt, spinner dolphins regularly occur in the resting areas of Samadai, Satayah and Qubbat'Isa reefs. In-water human interactions with dolphins are regulated with a time-area closure system at Samadai, unregulated at Satayah and non-existent at Qubbat'Isa. This provided an ideal experimental setting to advance our understanding of the effects of tourism on a species highly sensitive to disturbances. Our study confirmed that the intensity and duration of interactions, and therefore, dolphin exposure to tourism, differed among the study sites. Compared with the Qubbat'Isa control site, behavioural reactions to boats and swimmers at the two tourism sites suggested that dolphin rest was disrupted, especially around the middle of the day and especially at Satayah, where dolphin tourism is unregulated. Our results indicate also that the dolphin protection measures at Samadai reduce the level of disturbance. We recommend that similar measures be implemented at other dolphin tourism locations, and that no new operations be initiated until the long-term impacts on dolphin populations are better understood. Our experience emphasizes the need to adopt precautionary approaches in research and management of whale and dolphin watching.
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http://dx.doi.org/10.1098/rsos.172044 | DOI Listing |
Aquat Toxicol
December 2024
Department of Anatomy, Histology and Embryology, Faculty of Veterinary Medicine, University of Zagreb, Heinzelova 55, Zagreb 10000, Croatia.
In tissues of toothed whales from the Adriatic Sea (muscle, liver, kidney, lung, spleen, adipose tissue and skin) the concentrations of cadmium (Cd), lead (Pb) and arsenic (As) were analysed. In total, 186 dolphins were analysed; 155 bottlenose (Tursiops truncatus), 25 striped (Stenella coeruleoalba) and 6 Risso's dolphins (Grampus griseus). Cadmium concentrations in tissue samples ranged from 0.
View Article and Find Full Text PDFComp Biochem Physiol A Mol Integr Physiol
December 2024
Department of Animal and Food Science, School of Veterinary Science, Universitat Autònoma de Barcelona, Bellaterra, Spain; Animal Welfare Education Centre (AWEC), School of Veterinary Science, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Anthropogenic pressures and climate change present growing challenges for cetaceans, as the combined effects of multiple stressors can jeopardize their welfare and survival. In this context, validating reliable individual welfare indicators is crucial for quantifying these impacts. This study aimed to validate a method for measuring cortisol and oxytocin from the epidermis of stranded striped dolphins (Stenella caeruleoalba) using enzyme immunoassays, while accounting for confounding factors such as epidermal layer and body location.
View Article and Find Full Text PDFAnimals (Basel)
December 2024
Instituto de Investigaciones Marinas, Consejo Superior de Investigaciones Científicas, IIM-CSIC, 36208 Vigo, Spain.
In the last 25 years, nematode parasites of the genus have attracted international attention from various socio-economic sectors, with serious concern about the impact of these parasites on seafood quality and safety, and public health (related to both zoonoses and allergy). A knowledge-based understanding of the population structure of spp. is useful to provide valuable data about the infection dynamics, host specificity and its ability to adapt to local environments and to climate change by adapting to the food-web structure.
View Article and Find Full Text PDFSci Total Environ
December 2024
Aix Marseille Université, INSERM, SSA, MCT, 13385 Marseille, France.
The determination of 18 metals and metalloids was realized in 4 tissues of 62 Stenella coeruleoalba specimens stranded along the French Mediterranean coastline from 2010 to 2016. While most concentrations were comparable to mean worldwide levels, Hg levels were alarming (1190 μg g dw, in average). The results were discussed together with previous measurements in the same area, from 2002 to 2009.
View Article and Find Full Text PDFViruses
October 2024
Department of Comparative Biomedicine and Food Science (BCA), University of Padua, Viale dell'Università 16, 35020 Legnaro, PD, Italy.
Following the X-Press Pearl maritime disaster off the coast of Sri Lanka, a stranded spinner dolphin () was recovered, and the cause of death was investigated. Post-mortem examinations revealed evidence of by-catch, but a natural coinfection with dolphin morbillivirus (DMV) and gammaherpesvirus was detected by further analyses, marking the first documented case of a dual viral infection in this species within the region. Molecular diagnostics, including PCR and sequencing, were performed on tissue imprints collected on FTA cards, confirming the presence of DMV in the prescapular lymph node and gammaherpesvirus in the lesions in the oral cavity.
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