OBSERVATIONS OF FRESH-WATER JELLYFISH, CRASPEDACUSTA-SOWERBYI LANKESTER (TRACHYLINA, PETASIDAE), IN A WEST-VIRGINIA RESERVOIR

A swarm of medusae of the freshwater jellyfish Craspedacusta sowerbyi was observed in a cove of a West Virginia reservoir in August and Sept ember, 1995. Medusae were abundant (>1000/m(3)) but extremely localize d. Distribution of medusae in the cove did not appear to be linked to water chemistry. Size of medusae ranged from 6-21 mm in diameter and i ncreased significantly with distance from the center of abundance, sug gesting that the localized distribution of medusae resulted from dispe rsion rather than from environmentally-induced aggregation. Measuremen ts of mean diameter of medusae on separate dates indicated a growth ra te of about 0.2 mm/d, and a medusa life cycle of approximately 102 day s.