In July 2022, two Risso's dolphins were reported stranded in Hrútafjörður (N65° 09,503; W21° 05,529), a fjord in northern Iceland. These events represent the first confirmed observations and strandings of Risso's dolphins in Icelandic waters. Given the uniqueness of these events, a decision was made to conduct full necropsies on these individuals. This study reports findings from viral and parasitological investigations, morphological and fitness measurements, as well as stomach and intestine content analysis for each of the Risso's dolphin specimens. The results of the necropsies do not suggest any other cause of death than lack of food and exhaustion. A large plastic fragment in one individual's stomach supports these suggestions. The presence of those specimens in the middle of the subarctic ocean illustrates ongoing changes in spatial distribution expanding northward, impacting not only Risso's dolphins but more generally marine life and biodiversity.
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http://dx.doi.org/10.1002/ece3.10477 | 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 PDFPLoS One
October 2024
CIIMAR-Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Matosinhos, Portugal.
Animals (Basel)
August 2024
Departament de Sanitat i Anatomia Animals, Facultat de Veterinària, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
Neurobrucellosis in cetaceans, caused by , is a relevant cause of death in striped dolphins () from the Mediterranean Sea. Serological tests are not used as a routinary technique for the diagnosis of this infection. We briefly describe the pathological findings of nine free-ranging stranded cetaceans diagnosed with disease or infection in our veterinary necropsy service from 2012 to 2022.
View Article and Find Full Text PDFBioinspir Biomim
September 2024
School of Veterinary Medicine, National Taiwan University, Taipei 10617, Taiwan.
Like other odontocetes, Risso's dolphins actively emit clicks and passively listen to the echoes during echolocation. However, the head anatomy of Risso's dolphins differs from that of other odontocetes by a unique vertical cleft along the anterior surface of the forehead and a differently-shaped lower jaw. In this study, 3D finite-element sound reception and production models were constructed based on computed tomography (CT) data of a deceased Risso's dolphin.
View Article and Find Full Text PDFR Soc Open Sci
July 2024
Kelp Marine Research, Hoorn 1624 CJ, The Netherlands.
Social deep-diving odontocetes face the challenge of balancing near-surface proximity to oxygen and group members with foraging in the deep sea. Individuals rely on conspecifics for critical life functions, such as predator defence, but disperse during foraging to feed individually. To understand the role of social acoustic mediation during foraging in deep-diving toothed whales, we investigated the context of social burst-pulse call production in Risso's dolphin () using biologgers.
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