First recorded occurrence of the parasitic barnacle (Anelasma squalicola) on a Greenland shark (Somniosus microcephalus) in the Canadian Arctic.

A solitary Anelasma squalicola specimen was collected from the cloaca of a Greenland shark (Somniosus microcephalus), the first time this association has been recorded. The specimen's identity was confirmed through morphological and genetic assessment (mitochondrial markers: COI and control region). A. squalicola is a species typically associated with deep-sea lantern sharks (Etmopteridae) and, until the present observation, had never been observed at a sexually mature size in the absence of a mating partner. Given the reported negative effects of this parasite on its hosts, monitoring Greenland sharks for additional cases is recommended.