AME 17:99-103 (1999)  -  doi:10.3354/ame017099

Feeding by the small calanoid copepod Paracalanus sp. on heterotrophic dinoflagellates and ciliates

Kentaro Suzuki1,*, Yasuo Nakamura2,**, Juro Hiromi1

1College of Bioresource Sciences, Nihon University, Kameino, Fujisawa, Kanagawa 252-0813, Japan
2National Institute for Environmental Studies, Tsukuba, Ibaraki 305-0053, Japan
*Present address: Institute of General Science for Environment, Shin-Nippon Meteorological and Oceanographical Consultant, Riemon, Ohi-gawa, Shida, Shidzuoka 421-0212, Japan
**Addressee for correspondence. E-mail:

ABSTRACT: Feeding of the calanoid copepod Paracalanus sp. on natural populations of heterotrophic (h-) dinoflagellates and ciliates was examined during the summer in the Seto Inland Sea, Japan. Paracalanus sp. ingested h-dinoflagellates with clearance rates of 35 to 146 ml ind.-1 d-1, comparable to those for autotrophic (a-) dinoflagellates. Feeding rates of the copepod on h-dinoflagellates (0.35 to 0.93 μg C ind.-1 d-1) were close to, or in some cases exceeded, the basic metabolic demands (0.5 μg C ind.-1 d-1) of the copepod. Ciliates were also ingested by Paracalanus sp., but the corresponding clearance rates (23 to 60 ml ind.-1 d-1) were lower than those for h-dinoflagellates. These results, together with data on the abundance/biomass of Paracalanus sp. and h-dinoflagellates in the study area, indicate that the population of Paracalanus sp. can have a significant feeding impact on h-dinoflagellates.

KEY WORDS: Copepod · Heterotrophic dinoflagellate · Ciliate · Predation · Paracalanus

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