The marine leech Branchellion torpedinis parasitic on the angelshark Squatina squatina and the marbled electric ray Torpedo marmorata

Abstract

The marine leech Branchellion torpedinis is parasitic on teleost and elasmobranch species. Reports along its wide distribution range include the Carribean Sea, the Mediterranean Sea, and the west and east coasts of the North Atlantic Ocean. Most of these records are isolated cases and limited just to the mention of the relationship. In this sense, the present communication is a novel report and a reliable, long-term, host–parasite record for the marine leech B. torpedinis based on observations in its natural habitat, and an expansion of the known distribution of this helminth to include the Canary Islands. The leech was observed attached to the dorsum of the angelshark Squatina squatina and of the marbled electric ray Torpedo marmorata during a scuba diving census. No noteworthy aspects were registered in the attachment area, the behavior or apparent fitness of the hosts. These findings are important because it provides useful information about the dispersal patterns of a rare marine leech and its relationship with the hosts, and gives the first insights into a parasite for T. marmorata in the Canary Islands.