14 Conservation Department 



spawning' function of the bass. The disease is endemic in Lake 

 Erie and other Avaters of the St. Lawrence drainage system. It is 

 also showing up elsewhere in and out of the State. In small lakes 

 and ponds, such, for example, as are publicly or privately stocked 

 and in hatcliery ponds, the organism when established becomes 

 particularly menacing and for this reason, emphasis is placed on 

 continuing the study along lines of remedial measures. The life 

 history of this organism is now fairly well established. This is 

 shown pictorially on page 200. The picture will be complete 

 and cures effected, when certain of the remaining problems 

 are solved, — in the first place when the maximum period of 

 life in each of the intermediate hosts and the definitive hosts is 

 determined ; secondly, when it can be determined how' to break 

 successfully the life cycle, rendering the parasite controllable at 

 least in hatchery ponds. 



A third project in the follow-up group refers to ([uantitative 

 studies of the natural fish food supply using selected streams 

 in the watersheds covered. Both naturally stocked and hatchery 

 stocked streams are studied so that the results should aid not only 

 in determining the productive capacity of streams but in assisting 

 in the elucidation of some of our post-hatchery problems. 



Conditions of Pollution in Erie=Niagara Watershed. — 



Intensive and collaborative studies have been conducted to present 

 as adequately as possible the situation regarding conditions of 

 pollution in the watershed. Chemist, biologist, physiologist and 

 ichthyologist have furnished data helpful to the understanding of 

 these conditions. 



The chemists have shown that the relatively shallow shore 

 w^aters only receive the contributory influences of the inflowing 

 streams and the effects of the municipalities and industrial con- 

 cerns sewering into them. The graph (Fig. 2)* depicts the condi- 

 tions of the oxygen supply at distances of 500 and 2,000 feet from 

 the lake shore and 100 feet from shore in the Niagara river. The 

 bad condition in the harbor does not exist outside where the great 

 volume of water assimilates tlie Avastes and the oxygen su]:>ply is 

 good. On the Niagara river below Butt'alo where pollution is car- 

 ried ak)ng the river front, the oxygen sag is conspicuous. Tlie 

 cliaracterislic u])-swing in the curve is possible because of the 

 i-emarkable, natural endowment of this river in its volume of water 

 and in the rapids and falls Avhich provide the most stu]iendous, 

 natural aerating system in the world. 



Special studies of local area-; and profihvs of the more grossly 

 ])ollute(l sti'eams nvv given in the full i'('])oi-t. 



The bi()h)gist by examining dredge sami)les where a low oxygen 

 content is indicated adds most inii)ressively to the data supplied by 

 the chemist. This is cs|)('cially true hccausc of the greater stability 

 and ix'iMnancnee of condilions ;i1 the holloni. The (le|)osits of foul 

 sludges and llicir acconipauying foul wjilci- oi-ganisins ai'c thus a 

 fruitful if nol an agreeable aspect of llie study of existing eondi- 



*See pa-e 11:5. 



