NANFA-- Topeka shiner decline and FW jelly expansion

Hoover, Jan J ERDC-EL-MS (HOOVERJ_at_wes.army.mil)
Fri, 31 May 2002 15:45:49 -0500

Two very interesting articles in the June 2002 issue of Journal of
Freshwater Ecology:

"Spatial and temporal species associations with the Topeka shiner(Notropis
topeka)in Missouri," by Matthew R. Winston. This article uses fish data
from 1938 to present to look at changes in distribution. Topeka shiner
declined (along with 6 other species) and were negatively associated with
three expanding species: blackstripe topminnow, bluegill, and largemouth
bass. Unlike other declining species, Topekas retreated to smaller,
high-gradient streams. Results did not support physical/chemical causes for
Topeka declines (e.g., agriculture, urbanization, sedimentation,
channelization, etc.) but suggested biotic causes (e.g., predation,
competition, introduced diseases).

"First reports of the freshwater jellyfish Craspedacusta sowerby (Hydrozoa:
Olindiidae) from maritime Canada with a review of Canadian occurrences," by
D.F. McAlpine et al. Reviews records from 1934 to present, documents
northeasternmost record, and suggests that this apparently non-native
species is more common than thought.
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