Infestation of the Copepod Acartia tonsa with the Stalked Ciliate Zoothamnium

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Science  23 Oct 1964:
Vol. 146, Issue 3643, pp. 543-544
DOI: 10.1126/science.146.3643.543


An entire population of the copepod Acartia tonsa in the Patuxent River, Maryland, was infested with a stalked protozoan of the genus Zoothamnium. Each copepod had 25 to 200 ciliates attached around the appendages. The infestation occurred at the time when Acartia tonsa was being replaced as the dominant copepod by Acartia clausi.