Biological Survey — Erie-Niagara Watershed 161 



does not indicate that such water is fit for fish life, in the sense 

 of being a place where fish can maintain themselves naturally. 



(3) Dredging operations: Old fishermen agree that sturgeon 

 formerly spawned on bars which lay just off Buffalo harbor. These 

 bars have been removed by dredging. During the past summer 

 dredging was in progress in the upper Niagara river, at Straw- 

 berry island, which was an important spawning area for muska- 

 longe according to competent authority. 



(4) Lack of protection against fishing during the spawning 

 season : At this season, most species are concentrated on the spawn- 

 ing grounds, whether these places be areas in the lake, as occurs 

 in the case of the herring, or areas in creeks, as occurs in the case 

 of the common sucker. At this time, they are easiest to take in 

 large numbers and there is danger of destroying so many breeders 

 that future production thereby suffers. Most species are not pro- 

 tected against this danger, and commercial fishermen, anglers and 

 spear fishermen take many spawning fish. Sturgeon were very 

 heavily fished on their spawning beds in the past.^ Herring, 

 suckers, red-fin suckers and catfish are some of the species that 

 are so fished today. Can the supply keep up ? 



All types of fishing act, of course, toward a decrease in the num- 

 ber of fish, but fishing outside of the spawning season is a less 

 destructive process. 



(5) Diseases and parasites: During the summer there w^ere con- 

 siderable numbers of dead fish cast up on the shore of Lake Erie. 

 Although some of these appeared to be fish that had been dis- 

 carded by commercial fishermen because too small or in too soft 

 a condition to market, or because they were worthless species (as 

 stonecats), many w^ere fish killed by other than net injuries. A 

 great many perch die, in the warm months, from a disease which 

 appears as a large sore on the side. A fungus, Saprolegnia, was 

 evident on a dozen or more of such fish, which were examined. 

 The blue pike suffers from the same disease; apparently fewer 

 of this species were affected during this season, however. Whether 

 an initial injury is necessary before the disease will take effect is 

 not known. All fish seen that were from deep, cold water showed 

 no signs of the disease, while many that were taken from only 

 about 30 feet of water did have the disease. 



There are two species of parasitic lampreys in Lake Erie, which 

 live by sucking the blood of fish.^ One of the two (Petromyzon) 

 is very rare in the lake, and the other (Ichthyomyzon) does little 

 apparent damage. Lamprey injuries might offer opportunity for 

 disease to take effect, but at least the sores referred to -above are 

 not like the deep, round hole of a lamprey scar. Other parasites 

 of fish are discussed by Dr. Hunter. 



(6) Natural enemies, native or introduced: These may influence 



1 Smith, H. M. and'Snell, ]\Ierwin-Marie. Fisheries of the Great Lakes in 1885 

 Appendix 1, Report of U. S. Commissioner of Fish and Fisheries for 1887. 



2 Gage, S. H,, in Oswego Report 1927, pp. 158-191 gives an excellent account of 

 the natural history of lampreys. 



