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<br />
<br />
<br />
<br />ER 2, '(983
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<br />intermediate hosts, Althoug not the ocus fthe present study, other investigators
<br />have examined seasonal cha ges in ele s Lake plankton. Anderson and Lenat
<br />(1978) and Weiss and Ande son (19 8) eported that copepod densities rose in
<br />spring, peaked in mid-sum er, and ined to lowest levels by late fall. Thus,
<br />highest numbers of copepod were present during periods of warmest water tem-
<br />peratures and when activ cruitment of B. acheilognathi by G, affinis could be
<br />demonstrated experime tally, A similar pattern in seasonal dynamics of Both-
<br />riocephalus rarus w oted by Jarroll (1979), He observed peak densities of
<br />Mesocyclops aterat a time when active recruitment by the definitive host was
<br />also occurring.
<br />The spatial distributions of copepod intermediate hosts and G, affinis were also
<br />considered as potential factors in affecting the population biology of B. acheilo-
<br />gnathi, Mesocyclops edax and Cyclops bicuspidatus thomasi are limnetic in dis-
<br />tribution, and Tropocyclops prasinus is both littoral and limnetic (Pennak, 1966).
<br />Normally, mosquitofish are restricted to the shallow portions of the littoral zone,
<br />using vegetation for lateral concealment (Casterlin and Reynolds, 1977). Thus,
<br />G, affinis would normally be forced to prey primarily on T. prasinus, However,
<br />the absence of piscivorous fishes has permitted G, affinis to expand its lateral
<br />spatial distribution significantly in Belews Lake, Indeed, mosquito fish have been
<br />collected up to 300 m from shore, at the surface of water 40 m deep. Furthermore,
<br />uninfected mosquitofish fed plankton that had been collected 300 m from shore
<br />became infected with B. acheilognathi. This observation strongly suggests that
<br />transmission of B, acheilognathi is not confined to the littoral zone and that the
<br />spatial distribution of copepod intermediate hosts is not a factor affecting the
<br />population biology of the cestode in Belews Lake.
<br />
<br />OF WASHINGTON, VOLUME 5
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<br />Acknowledgments
<br />
<br />This study was supported, in part, by a grant from the Wake Forest University
<br />Research and Publication Fund. We thank Mr. Michael Riggs for allowing us to
<br />use some of his unpublished observations on diet preferences of mosquitofish in
<br />Belews Lake and for his assistance with the statistical analyses. We appreciate the
<br />dialogue with Dr. Glenn Hoffman regarding the taxonomy of B, acheilognathi,
<br />as well as the translation of the Dubinina (1982) reference by Dr. Hilda Ching,
<br />
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<br />Anderson, R. M. 1976, Seasonal variation in the population dynamics of Caryophyllaeus laticeps,
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<br />Anderson, T, P., and D. R. Lenat, 1978, Effects of power-plant operation on the zooplankton
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