20 THE REPORT UPON No. 36 



bringing untoward conditions regarding pollution of our lakes and streams to 

 the notice of the Department and lead to more intensive studies and corrective 

 measures. 



Pound- Netting: 



The subject of pound-netting, on which there has been considerable dis- 

 cussion and controversy between gill net fishermen on one hand and pound net 

 fishermen on the other, was studied particularly in the vicinity of Rondeau, 

 Lake Erie, where experimental nets with meshes in the backs of the cribs, ranging 

 in size from 1^ inches to 33^ inches, have been run throughout the summer. 

 In addition, the methods employed by the fishermen in their operation of pound 

 nets were studied along the entire north shore of the lake. 



To be ideal the crib of a pound net should have a mesh sufficiently large 

 to allow all immature fish to escape. Such a condition also reduces the extent 

 to which such fish are handled during the sorting process. It is not unreasonable 

 to believe that if the above conditions are met, the mortality among the immature 

 fish will be greatly reduced. However, it has been found that a large mesh in 

 the crib gills a certain proportion of marketable fish which reduces their value 

 to the fishermen, and that in some instances fish of legal size may escape through 

 the meshes. At least another season's experimentation with nets is necessary 

 before final recommendations can be made regarding the mesh or meshes of 

 netting in the crib, in order to be satisfactory from most, if not from all angles. 



Coarse Fish and Hoop-Netting: 



The advisability of taking coarse fish from our waters requires a lengthy 

 discussion, but an answer to the wholesale destruction of predatory fish resolves 

 itself to this — if these fish are not interdependent with game fish, either directly 

 or indirectly, or exist in such abundant numbers that it appears impossible 

 for game fish to re-establish themselves, a reduction in the number of coarse 

 fish is considered a wise policy. One reason for granting hoop net licenses is 

 to help, theoretically, in maintaining a balance between game fish and coarse fish. 



Certain fish like the gar-pike and dog-fish are of little value as food and 

 are known to eat the more useful kinds. However, it is not wise to condemn 

 any species without exact knowledge. An interdependence exists among 

 the different forms of life in lakes or streams, which cannot be overlooked. 

 For example, the species of minnow, namely, the golden shiner (Notemigonus 

 crysoleucas) provides food for the black bass from the lime the bass is large 

 enough to eat fish. In fact, this species is used in the culture of bass in the 

 United States, and this year we have made its culture an adjunct to our hatcheries. 

 Nevertheless, if a nest is left unguarded by a bass which may wander temporarily 

 from its nest, the golden shiner has been known to approach the nest and eat 

 deposited spawn. This knowledge, however, would not lead us to exterminate 

 the valuable food of the bass which this species of minnow provides. The 

 same principle applies to the value of the immature sucker as food for pike, 

 pickerel and bass. 



Considerable criticism has come from anglers in regard to the operation 

 of hoop nets in certain of our waters, and this led to a study of the effect of 

 hoop-netting on game fish in the waters of the Rideau System and Lake Ontario. 



Initial studies have not shown that hoop-netting as such interferes with 

 our game fish before the first of May when the latter commence to move into 

 shallow water. These studies were supplemented by statistics collected from hoop- 



