The Food of Ciscoes (Leucichthys) in Lake Erie. 
By WILBERT A. CLEMENS, 
AND 
N. K. BIGELow, 
University of Toronto. 
The results of the examination of the contents of the digestive tracts of 
211 ciscoes (fresh-water herring) are presented herein. The bulk of the material 
was obtained early in June, 1919, and from July to November in 1920, from 
Lake Erie at various points along the north shore. The species examined were 
Leucichthys eriensis, the jumbo cisco; L. artedi, the Lake Erie cisco; L. sisco 
huronius, the Lake Huron cisco; and L. prognathus, the Lake Ontario deep 
water cisco (longjaw). These were taken at Merlin, Rondeau, Port Dover, 
Nanticoke, McKillop’s fishery (near Port Maitland), and Dunnville. In 
addition 19 individuals of L. harengus, the Georgian Bay cisco, from Wiarton, 
Georgian Bay, and 7 individuals of L. ontariensis, the Lake Ontario cisco, from 
Port Credit, Lake Ontario, have been examined for comparative purposes. 
The material from Merlin, Rondeau, Nanticoke and McKillop’s was obtained 
in pound nets while the material from all the other points was obtained in gill 
nets. 
The results are given in the following tables. In the table “‘ Unidentified 
species’’ are placed those fish whose identity was not determined. The figures 
indicate the relative abundance, namely: (1) that only a few individuals were 
noted; (2) that the organisms occurred rather abundantly; (3) very abundantly. 
SUMMARY: 
1. An examination of the tables shows that the ciscoes are pre-eminently 
plankton feeders. The study practically covers the fishing season, and during 
that time at least, the free swimming crustacea form the bulk of the food of 
these fish. Of Canadian waters, Lake Erie produces more ciscoes than all the 
other Great Lakes combined. For example, in 1919 Lake Erie produced 
7,425,713 lbs., while the remainder of the Great Lakes produced 4,022,711 Ibs. 
It is not improbable that the production of ciscoes is directly dependent upon 
the amount of plankton Crustacea produced. The numbers of these Crustacea 
which must abound in Lake Erie in order to support the millions of ciscoes, as 
well as the great numbers of white fish and young of many other species, is 
almost beyond the imagination. Comparative quantitative plankton studies 
in the Great Lakes would, no doubt, afford considerable information as to the 
fish productive capacities of these lakes. 
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