Journal of Shellfish Research, Vol. 22, No. 1, 495-500, 2003.

PATTERNS OF EMERGENCE AND SURVIVAL OF CONCHOPHTHIRUS ACUMINATUS (CILIOPHORA: CONCHOPHTHIRIDAE) FROM DREISSENA POLYMORPHA (BIVALVIA: DREISSENIDAE)

ALEXANDER Y. KARATAYEV^1,*, SERGEY E. MASTITSKY², DANIEL P. MOLLOY³, AND LYUBOV E. BURLAKOVA¹

¹ Department of Biology, Stephen F. Austin State University, Nacogdoches, Texas 75962-3003;

² General Ecology Department, Belarussian State University, 4 Skoryna Ave., Minsk, 220050 Belarus;

³ Division of Research & Collections, New York State Museum, Albany, New York 12230

*Corresponding author. E-mail: akaratayev@sfasu.edu

ABSTRACT: This is the first study to quantify the periodic emergence of a Conchophthirus sp. from its bivalve host. Emergence rates of C. acuminatus from Dreissena polymorpha over the entire 24-day experiment appeared to be directly correlated with infection intensity. The rate of ciliate emergence from individual mussels varied considerably throughout the experiment at both 14°C and 21°C. It was not uncommon to have a sampling period in which no emergence was observed immediately followed by a period of high emergence, e.g., at 14°C from 0 to 25 ciliates and at 21 °C from 0 to 720 ciliates. The total mean number of ciliates that were observed to have emerged from each mussel during the 24-day experiment was significantly higher at 21°C (207 ciliates/mussel) than at 14°C (29 ciliates/mussel). Our experiments suggested that C. acuminatus have a short survival period outside their host. Although we observed a maximum survival period of 144 hr (6 days), most ciliates died within 48 h.

KEY WORDS: Conchophthirus acuminatus, ciliate, commensal, host, bivalve, Dreissena polymorpha, zebra mussel, mantle cavity