THE FISHES OF GEORGIAN BAY ' 17 



SESSIONAL PAPER No. 39b 



Upper parts with more or less golden reflections. Dorsal fin with 11 to 13 rays, 

 usually 12. Anal fin with 7 or 8 rays. Scales of medium size, but rather small 

 and crowded forwards, 9 or 10, 64 to 72, 7 to 9. Young specimens taken in the 

 shore swamps show blackish blotches on the sides. 



Like the remaining members of this family, the common sucker is a bottom- 

 feeding fish, subsisting ordinarily on molluscs and crustaceans, but very destructive 

 to the spawn of other fishes. The present species is abundant on the shoals where 

 the whitefish, trout, and herring resort in the fall for spawning purposes. It 

 also runs into the rivers, to the foot of waterfalls in the early spring, feeding on 

 the spawn of the dore, and afterwards spawning in the same situation. It is not 

 infrequently seen swimming lazily about in the shallow water of the swamps in 

 June, during the spawning time of the rock-bass and black bass, and on some 

 occasions has been observed to enter the nests of these fishes, apparently with 

 little resistance on the part of the occupants, and leisurely devour the contents. 



Family cyprinidae. 

 (Carps and minnows) 



This family is represented in Georgian Bay waters by at least five genera and 

 ten species. One species, the common or Geiman carp, is an accidentally intro- 

 duced species for these waters. In addition there are three species, representing 

 two more genera, the normal occurrence of which is doubtful. These are the red- 

 bellied dace {Chrosomus erythrog aster) and the black-nosed dace {Rhinichthys 

 atronasus) , single specimens of which appear in the collections ; and a species of 

 Semotilus or Hyhopsis, represented by a single specimen, too minute for identifi- 

 cation, which was taken with specimens of Rhinichthys in a rock pool. 



With the exception of the carp, these species are all of small size, Georgian 

 Bay specimens appealing in general small in comparison with those of other locali- 

 ties southward. The largest species in the region is the redfin minnow (Notropis 

 cornutus), which is commonly 3^ inches in length, and the smallest is Notropis 

 heterodon, which is barely an inch in length. 



Though of small size, the Cyprinidae are of the greatest importance, since they 

 form the food of larger fishes such as the bass, pike, and dore, either diiectly, or 

 indirectly through the crayfish, which feed on smaller fishes to a considerable extent, 

 and themselves form the staple food of the small-mouthed black bass and rock- 

 bass. The Cyprinidae are in fact the intermediates in the range of food supply, con- 

 necting the larger fishes with the fundamental plankton food of the water, since 

 they live very largely on small or microscopic entomostraca, blue-green and green 

 algae, and minute insects. They are not wholly benefactois, however, for it is 

 probable that enormous numbers of eggs of nesting fishes are destroyed in the spring 

 of the year by the vaiious species infesting the shore swamps. They annoy the 

 nesting bass and rock-bass by their enormous numbers, and the temporary depar- 

 ture of the fish from the nest is a signal for a swift attack on the contents, which are 

 devoured in a moment. Specimens taken under such circumstances commonly 

 have the stomach gorged with the stolen eggs. 



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