Contributions to Canadian biology . B Fig. 1.—Drawings of scales of ciscoes. A, from specimen No. 606, L. artedi, showing 5 winter bands, the fish therefore being in itssixth summer. B, from specimen No. 235, L. eriensis, showing three winter bands, the fishtherefore being in its fourth summer. From Georgian Bay. 2From Lake Ontario. 80 Rates of GrowthThe scales were used in determining the rates of growth of the various speciesof ciscoes. The growth areas are usually well marked. Scales from approxi-mately the following number of fish of each species were examined: L. eriensis. 5 10 15 20 25 3
Contributions to Canadian biology . B Fig. 1.—Drawings of scales of ciscoes. A, from specimen No. 606, L. artedi, showing 5 winter bands, the fish therefore being in itssixth summer. B, from specimen No. 235, L. eriensis, showing three winter bands, the fishtherefore being in its fourth summer. From Georgian Bay. 2From Lake Ontario. 80 Rates of GrowthThe scales were used in determining the rates of growth of the various speciesof ciscoes. The growth areas are usually well marked. Scales from approxi-mately the following number of fish of each species were examined: L. eriensis. 5 10 15 20 25 30 35 40 45 Length in Centimeters Fig. 2.—Graph illustrating rates of growth of ciscoes in Lake Erie a = L. artedi, p = L. prognathus,e = L. eriensis, sh=L. sisco huronius. 81 10 140; L. artedi 55; L. sisco huronius 55; L. prognathus 150. The results areshown in Fig. 2. Considerable difficulty was experienced in estimating therate of growth of L. sisco huronius. In the majority of scales some of the winterbands were difficult to distinguish and there was evidence that in some cases atleast one winter band was not recorded. It is possible, therefore, that thecurve for this species should lie to the left of the curve for L. eriensis. Fig. 3shows the relation of age to weight. The following table gives the data obtainedfor the three important commercial species in Lake Erie. The length in centi-meters is from the tip of the snout to the base of the caudal fin; the girth justanterior to the dorsal fin.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectnaturalhistory, booky
