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Peterson, Walter F. (ed.) / Transactions of the Wisconsin Academy of Sciences, Arts and Letters
volume LX (1972)

Howmiller, Richard P.; Ludwig, G. M.
A record of Craspedacusta sowerbyl in Wisconsin,   pp. 181-182 PDF (538.0 KB)

Page 181

Richard P. Howmiller and G. M. Ludwig 
 The freshwater jellyfish, Craspedacusta sowerbyi, is reported for the first
time from Wisconsin. Large numbers of medusae occurred in a small artificial
pond in late summer of 1969 and 1970. This appears to be the northernmost
locality for the species in the Mississippi drainage. 
 The known North American distribution of the freshwater jellyfish, Craspedacusta
sowerbyi Lankester, is broad but appears to be centered in the northeastern
quarter of the United States. There seem to be no previous records of this
species as far north in the M'ississippi drainage as Wisconsin (Pennak 1957,
Lytie 1960, Bushnell and Porter 1967). As pointed out by Pennak (1957) the
lack of reported occurrences in this region are remarkable because of the
considerable limnological knowledge of Wisconsin and Minnesota. 
 A medusa brought to the Milwaukee Public Museum for identification directed
our attention to a population of C. sowerbyi in a small pond on Skillet Creek
Farm (N ½ Sec 15, T 11 N, R 6 E) near Baraboo, Sauk County, Wisconsin.
The pond is approximately 50 m in diameter, dug in glacial till and fed by
water from Skillet Creek. Dug six years ago, the pond still appears "new"
with a bottom of sand and gravel and no colonization by aquatic macrophytes.
Medusae of C. sowerbyi have been noticed by the owner in the fall of 1969
and 1970. When we visited the pond on September 13, 1970, large medusae (1.0—1.5
cm) were abundant; we captured more than 50 with small hand nets in an hour.
Some medusae swam to the surface of the water and floated downward again.
Others lay, pulsing slowly, on the bottom in patches of filamentous algae
(Spiro gyra) and detritus. Crayfish, amphipods, ostracods, chironomid larvae,
mayfly nymphs and the gastropods, Campeloma and Ferrissia, were common in
the algae and detritus. Poiyps of C. sowerbyi were not observed. 
 O Contribution No. 43, Center for Great Lakes Studies, University of Wisconsin—
Milwaukee, Milwaukee, Wisconsin 53201 

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