Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2023

Hiding in plain sight: larval tapeworms provide insights into management of a fish species.

Höfundar / Authors: Haseeb Randhawa (1,2,3)

Starfsvettvangur / Affiliations: 1. Faculty of Life and Environmental Sciences, University of Iceland, Reykjavík, Iceland, 2. South Atlantic Environmental Research Institute, Stanley, Falkland Islands, 3. New Brunswick Museum, Saint John, New Brunswick, Canada

Kynnir / Presenter: Haseeb Randhawa

The identification of marine tapeworm larvae remains problematic given the lack of morphological features available for specific identifications. For instance, larvae of the Tetraphyllidea (s. l.) have commonly been referred to as Scolex pleuronectis, Scolex polymorphus or simply as “tapeworm plerocercoids” (TP) in numerous host-parasite checklists or parasitological surveys. Here, I present a case study where increased taxonomic resolution using molecular tools provides insights into fisheries management. Previous surveys have reported high prevalences of TP in rock cod (as a single operational taxonomic unit, OTU). A recent study revealed that tetraphyllidean (a type of tapeworm) plerocercoids were a potential biological tag to discriminate between rock cod stocks from the High Seas north of the Falklands and from waters on the southern Patagonian Shelf. A parasitological survey in 2018 of 503 rock cod (Patagonotothen ramsayi) collected from the Patagonian Shelf found a prevalence of infection of TP in rock cod of 23%. Molecular characterisation using partial 28S rDNA sequence data was used for specific identifications. The presence of six distinct species of TP was confirmed in rock cod. Since TP (as an OTU) has been identified as a potential biological tag for stock discrimination of rock cod in the southwest Atlantic, I suggest that improved taxonomic resolution will increase the discriminatory power of analyses and provide more accurate tools for the management of this