OBSERVATIONS ON THE MARINE LEECH CALLIOBDELLA CAROLINENSIS (HIRUDINEA: PISCICOLIDAE), EPIZOOTIC ON THE ATLANTIC MENHADEN

¹ Department of Biology, College of Charleston, Charleston, South Carolina 29401
² South Carolina Marine Resources Center, Office of Conservation, Management and Services, P.O. Box 12559, Charleston, South Carolina 29412

1. In January through March, 1971, and to a less extent the same period in 1972 and 1973, the marine leech, Calliobdella carolinensis Sawyer and Chamberlain 1972, was epizootic on the Atlantic menhaden, Brevoortia tyrannus, in the estuaries of South Carolina. Prior to this epizootic outbreak (epidemic) the leech was practically unknown.

2. The population dynamics of this outbreak were studied near Charleston, South Carolina, for three years, primarily in an estuarine creek and in the surf zone of an exposed beach.

3. Calliobdella carolinensis displays a seasonal occurrence which correlates with the temperature of the water. The leeches reach their greatest abundance in late February and early March, when the water is coldest (9 to 10° C). At that time the leeches breed and deposit at least 20 helmet-shaped cocoons. No leeches are found from the end of April until the following mid-December.

4. The leech occurs primarily in the estuaries of South Carolina, and is reported also from Virginia. It is not known south of South Carolina.

5. Feeding, reproductive behavior, growth, life cycle, salinity tolerance and other aspects of the biology of C. carolinensis are described.