92 Conservation Department 



of fish was made, consisting* of only three species : German 

 carp, blunt-nosed minnow and common sucker. No other varieties 

 were collected or reported by persons familiar with the stream at 

 this point. 



The same body of water near Phelps, 14-miles below, had com- 

 pletely recovered from the pollution as judged by the clean 

 character of the water and the presence of clean water insect life. 

 Collecting here with a seine yielded 10 species of fish: small- 

 mouthed black bass, rock bass, fallfish, hornyhead, cut-lips 

 minnow, Johnny darter, fan-tailed darter, common sucker and hog- 

 sucker. 



We might say that Canandaigua outlet illustrates the injury 

 done by a comparatively slight pollution in upsetting the natural 

 conditions in a stream. This has resulted in destroying the food 

 supply of certain species of fish, as in this case, the small- 

 mouthed black bass, while not seriously interfering with that of 

 others, such as the common sucker. 



Minnow Tests. — The generally accepted test of the injurious 

 effect of pollution is the minnow test. This consists in placing a 

 number of small fishes in such container that they are in direct 

 contact with the water. During the summer several experiments 

 of this character were made in polluted streams, and these waters 

 were also carefully studied in regard to their fish fauna. It was 

 found that the minnows in the test were not usually killed by the 

 contaminated water even though the entire absence of fish as 

 well as the general condition of the stream clearly indicated that 

 it was unfit to support fish life. 



On August 25, 1927, a minnow test was made in a seriously 

 polluted stream, Skaneateles outlet near Skaneateles Junction, 

 at a point where all native fishes were absent, In spite of the very 

 bad pollution the minnows in this experiment were not killed but 

 lived for several hours without apparent ill effects. The oxygen 

 test, made by Mr. Wagner, at this time was 3.3 parts per million, 

 low but evidently not low enough to kill. On a very hot day a 

 short time before, the oxygen test was 1.4 parts per million un- 

 doubtedly below the requirement of fishes. Had a test been made 

 at this date the minnows would have lived only a short time. So 

 that, if judged by the one experiment made, this stream would 

 give a misleading impression. Similar tests made in other polluted 

 areas (Keuka outlet and Owasco outlet) merely indicated that 

 small fish could live for at least several hours in waters certainly 

 unfit to maintain them, as judged by their complete absence. 



It may be concluded from these experiments that a minnow 

 test does not form a wholly adequate criterion for judging the 

 capability of a stream to support fish life. 



Special Problems 

 The Spawning Behavior of Carp in Relation to Other 

 Fish. — During their breeding season, in the spring, carp con- 

 gregate in schools. The eggs are shed and fertilized, the process 

 being accompanied by vigorous agitation and splashing. There 



