Description of hyperostotic bones pattern in Largehead Hairtail Trichiurus lepturus

Abstract

Several studies have documented the occurrence of hyperostosis, a bone condition that results in bone thickening, in specimens of Trichiurus lepturus, an important commercial species. A total of 102 Largehead Hairtail fish samples from Rio de Janeiro, Brazil, were obtained from artisanal fishers and divided into 4 size classes. Biometric measurements and radiographic images were taken for all exemplars. Hyperostosis was observed in 69.69% of the individuals, with the first detection of the condition in an exemplar measuring from 385 mm in total length. The affected skeletal regions included the cleithrum, supraoccipital, frontal, dorsal pterygiophores, and haemal spines. An increase in the occurrence frequency of hyperostosis was noticed in correlation with size, suggesting a connection with the aging process and an ontogenetic pattern for the species. Histological analysis indicated a high remodeling process in affected structures. In addition, we highlight the specie daily vertical migration, associated with temperature variation, as a potential contributor to the onset of this osteological condition in marine teleosts.