2014 Volume 76 Issue 2 Pages 129-138
We documented the distribution and life history of the tapeworm, Proteocephalus tetrastomus (Cestoda, Proteocephalidea, Proteocephalidae) in the pond smelt, Hypomesus nipponensis in Japan. Infection with P. tetrastomus was confirmed in pond smelt populations from 19 of 34 lakes we sampled. The distribution of P. tetrastomus ranged from Hokkaido to the Kinki region, and was not significantly biased to either freshwater or brackish, nor to any trophic status of the lakes. There was no significant negative relationship between the abundance of tapeworms and the condition factor of infected fish in any of the lakes. Year-round sampling in Lake Ogawara revealed that P. tetrastomus grew and developed in the pond smelt from spring through summer. Gravid worms were present from June through December, and small juveniles were first documented in July. The number of juveniles increased up to late autumn and remained high during winter. These seasonal changes suggest that P. tetrastomus is basically univoltine, and the generation turnover occurs primarily from summer to autumn.
