Population biology and host-parasite relationships of Triganodistomum attenuatum (Trematoda: Lissorchiidae) infecting the white sucker, Catostomus commersoni (Lacépède).

Triganodistomum attenuatum demonstrated similar seasonal infection patterns in white suckers, Catostomus commersoni, from the Bellamy and Oyster rivers, New Hampshire. Mean intensity was highest in spring 1975 and 1976. Nongravid and gravid worms were common in the spring, and in the spring and summer, respectively. Most individuals of T. attenuatum parasitized the posterior portion of the sucker's intestine. No definite changes in prevalence and mean intensity were evident at either river as fish size increased. Male and female suckers had similar prevalences and mean intensities of infections. Although a significantly larger number of suckers from the Oyster River was infected than from the Bellamy River, the mean intensities were similar. Triganodistomum attenuatum was found to be host specific to the white sucker. Other fish species examined for the presence of T. attenuatum were as follow: creek chubsucker (Erimyzon oblongus), fallfish (Semotilus corporalis), golden shiner (Notemigonus crysoleucas), bridle shiner (Notropis bifrenatus), common shiner (N. cornutus), longnose dace (Rhinichthys cataractae), redfin pickerel (Esox americanus), pumpkinseed (Lepomis gibbosus), and swamp darter (Etheostoma fusiforme). The state of New Hampshire is a new locality record for T. attenuatum.