REPRODUCTIVE-BIOLOGY OF 4 SPECIES OF FRESH-WATER MUSSELS (MOLLUSCA, UNIONIDAE) IN THE NEW RIVER, VIRGINIA AND WEST-VIRGINIA

The gametogenic cycle, spawning and glochidial release periods, and age at sexual maturity were determined for four unionid species from the New River in Virginia and West Virginia: mucket, Actinonaias ligamentina; spike, Elliptio dilatata; purple wartyback Cyclonaias tuberculata; and pistolgrip, Tritogonia verrucosa. The mucket is a long-term brooder, spawning in mid-summer, brooding glochidia throughout fall and winter, and releasing them in spring. The spike, purple wartyback, and pistolgrip are short-term brooders. Spawning began in mid-March and continued into May for T. verrucosa, into June for C. tuberculata, and into July for E. dilatata. Glochidia were released upon maturation, beginning in mid-April and continuing through June for T. verrucosa, into August for E. dilatata, and extending from March through June for C. tuberculata. All four species are sexually mature at 4 to 6 years of age.