Fatal asphyxia due to laryngeal displacement by large-sized prey in a Guiana dolphin (Sotalia guianensis), Brazil

Abstract

The Guiana dolphin (Sotalia guianensis) is a small odontocete distributed from Santa Catarina state, Brazil, to Honduras. Although it is currently considered “near threatened” by the International Union for Conservation of Nature, considerable knowledge on health and disease aspects of this species has been gained over the last decade. The main threats for the species are represented by multiple anthropic factors. Guiana dolphins feed on a variety of taxa, primarily teleosts, crustaceans, and cephalopods. Herein, we reported a case of severe laryngeal displacement and esophageal impaction with ulceration associated with a deglutted adult leatherjacket (Oligoplites sp.). This fish species is not a common prey item of Guiana dolphins’ diet. Severe upper aerodigestive compromise likely led to death by mechanical asphyxia (choke) in this dolphin. This report attested the occurrence of upper aerodigestive dysfunction due to overzealous feeding in Guiana dolphin and contributed to general knowledge on pathology of the species.

Macro and microanatomy of some organs of a juvenile male Ganges River dolphin (Platanista gangetica spp. gangetica)

“…appendages show that the dolphin was once a land animal. Similarly, the respiratory system of dolphins follows a similar pattern to terrestrial mammals (Mariani et al, 2020). However, to avoid aspiration while feeding, some adaptive changes, such as blowholes instead of the nostril, are present in dolphins.…”

Fine‐scale distribution of the lungworm Halocercus delphini in the lungs of the striped dolphin, Stenella coeruleoalba: implications about migration pathways and functional significance

“…Cetaceans are peculiar in that their respiratory system is largely isolated from the digestive system. Their larynx extends through the esophagus into the nasal passage and is sealed into place by the palatopharyngeal sphincter muscle, which allows food to pass on either side of the larynx (Bueno Mariani et al, 2020; Reidenberg & Laitman, 1987). It is still possible that lungworm larvae can reach the gut as in terrestrial metastrongyloids, but this pathway is not expected to be easy to follow.…”

Postmortem of a juvenile male Ganges River dolphin (Platanista gangetica spp. gangetica) in Bangladesh

“…Dolphins, irrespective of the region, commonly encounter infectious diseases, 16 verminous pneumonia, 16,25 acute underwater entrapment, 25,26 choking [27][28][29] and others such as pulmonary oedema, 15,16 vascular congestion, 16,30 gas embolism 16,31 and neoplasia. 16 To date, cases of Ganges River dolphin entanglement in fishing nets have been reported.…”