Attachment sites of parasitic lampreys: comparisons among species

Abstract

Distribution of attachment sites varies with the species of lamprey being considered. Large anadromous species (Petromyzon marinus and Lampetra tridentata) tend to attach ventrally, especially near the pectoral fins, while smaller freshwater species in shallow habitats (Ichthyomyzon castaneus and I. unicuspis) and species that feed on muscle tissue (Lampetra ayresi) tend to attach dorsally. Catostomids tend to be attacked on the head and, by the Ichthyomyzon species, on the paired fins. Distribution of attachments by P. marinus in laboratory studies may be affected by tank size. Attachments to the head and pectoral regions are probably associated with greater host mortality rates and may be underrepresented in field samples. Attachments to the pectoral region appear to combine low costs, in terms of handling time prior to feeding, with greater rates of energy intake once feeding has been initiated. Dorsal attachments by species that inhabit relatively shallow rivers and streams may be a compromise to avoid abrasion against the bottom. A consequence of dorsal attachments may be a reduced impact on host populations through prolonged attachments to individual hosts and reduced attack rates.