Vertebral column deformities in white-beaked dolphins from the eastern North Atlantic

Abstract

Five white-beaked dolphins Lagenorhynchus albirostris with outwardly vertebral kyphosis, kyphoscoliosis or lordosis were identified during a photo-identification survey of over 400 individuals (2002-2013) in Faxaflói and Skjálfandi Bays, Iceland. In addition, 3 stranding reports from Denmark, The Netherlands and the UK were analysed, providing both external observation and post mortem details of axial deviations of the vertebral column in this species. Two of the free-ranging cases and 2 of the stranded specimens appeared to have an acquired disease, either as a direct result of trauma, or indirectly from trauma/wound and subsequent infection and bony proliferation, although we were unable to specifically identify the causes. Our data represent a starting point to understand vertebral column deformations and their implications in white-beaked dolphins from the eastern North Atlantic. We recommend for future necropsy cases to conduct macro- and microscopic evaluation of muscle from both sides of the deformed region, in order to assess chronic or acute conditions related to the vertebral deformations and cause of death.

Visual health assessment of white‐beaked dolphins off the coast of Northumberland, North Sea, using underwater photography

“…A similar case was described in a juvenile male L. albirostris stranded in Bridlington, England, in 1995 (Bertulli et al . , Fig. ).…”

“…; Bertulli et al . ). Cetacean morbillivirus repeatedly induced morbidity and mortality in L. albirostris along the shores of Germany and The Netherlands (Osterhaus et al .…”

“…Anthropogenic interaction was deemed the most likely origin, as the flukes of this dolphin had also been partially severed (Bertulli et al . ). Another juvenile male stranded on Terschelling, The Netherlands, in January 1999, also presented a wound behind the dorsal fin together with deformation of the vertebral column and skin marks and lacerations suggestive of a fishery interaction (Bertulli et al .…”

“…Another juvenile male stranded on Terschelling, The Netherlands, in January 1999, also presented a wound behind the dorsal fin together with deformation of the vertebral column and skin marks and lacerations suggestive of a fishery interaction (Bertulli et al . ). As deep oblique incisive wounds on the back of small cetaceans are often of anthropogenic origin (Visser , Van Waerebeek et al .…”

Visually Detectable Vertebral Malformations of a Bottlenose Dolphin (Tursiops truncatus) in the Mississippi Sound

“…Moreover, Kranenbarg et al (2005) demonstrated that lordotic vertebrae in European sea bass (Dicentrarchus labrax L.) became acclimated to the increase of lateral muscle activity and bending movement by having greater bone deposition than normal vertebrae. It should be noted, however, that some causes of vertebral malformations, such as trauma, may also cause secondary ailments, such as infection (Bertulli et al, 2015), making it difficult to ascertain the role of the abnormality in assessing the animals' longevity in some cases.…”