Biological Survey — Oswego Watershed 



201 



The Relative Abundance and Kinds of Animals Taken in 

 the Stream Drift Studies. — Considering per cents (Table 5) 

 over the entire three months, it is seen that the flies were numeri- 

 cally dominant constituting 38.46% of all the animals taken and 

 hence furnished one large possible source of food for the trout. 

 Mayflies came second making up 28.94% of the total, while stone- 

 flies formed 3.43%, caddisflies, 1.43% and butterflies and moths 

 only .36% of the total number collected. The mayflies, stoneflies 

 and caddisflies having aquatic larval stages are available as 

 food for trout during their entire life cycle. Ants, bees and wasps 

 formed 4.33% of the total number and have long been known to 

 furnish excellent food for trout. Both larvae and adults of the 

 butterflies and moths are good trout food, but do not seem to 



Table '5. — Showing Available Fish Food Taken feom Streams in Drift Net 



by Month 

 (Given in numbers and per cent by order) 





June 



July 



August 



Total 

 num- 

 ber 



Per 



cent 



ORDER 



Num- 

 ber 



Per 

 cent 



Num- 

 ber 



Per 



cent 



Num- 

 ber 



Per 

 cent 





629 



548 

 483 



102 

 100 

 85 

 27 

 18 

 17 



15 

 8 



30.95 

 26.97 

 23.77 



5.02 

 4.92 

 4.18 

 1.33 

 0.89 

 0.84 



0.74 

 0.39 



1,173 

 623 

 218 



34 

 65 

 25 

 22 

 12 

 104 



'"is 



51.2 

 27.19 

 9.52 



1.54 

 2.84 

 1.09 

 0.96 

 0.52 

 4.54 



*6!65 



242 



367 



91 



94 

 39 

 39 



27 



8 



61 



4 

 19 



24.42 



37.03 



9.18 



9.49 

 3.94 

 3.94 

 2.73 

 0.81 

 6.16 



0.4 

 1.91 



2,044 



1,538 



792 



230 

 204 

 149 

 76 

 38 

 182 



19 

 42 



38.46 



Mayflies (ephemerida) 



Aphids et al. (homoptera) . . . 

 Ants, bees and wasps (hyme- 



28.94 

 14.91 



4.33 



Beetles (coleoptera) 



3.84 

 2.80 



Caddisflies (trichoptera) .... 

 Spiders and mites (arachnida) 



Stoneflies (plecoptera) 



Butterlies and moths (lepi- 



1.43 



.72 



3.43 



.36 





.79 







Totals 



2,032 



100.00 



2,291 



100.05 



991 



100.02 



5,314 



100 01 







be generally available as very few were taken in the drift net. 

 Beetles and bugs occurred in the catches in about the same num- 

 bers and are generally considered as second rate food because of 

 their very hard, thick, chitinous exoskeletons and usually small 

 size. Aphids and their near relatives, while they formed 14.91% of 

 the total number of animals taken, offer little actual food for trout 

 on account of their exceedingly small size. Members of other 

 orders of insects which Embody and Gordon* list as being found 

 in trout stomachs, but which were not taken in these drift studies, 

 were adult fishflies and grasshoppers. In the miscellaneous list 

 are included a few leeches, hairworms, springtails, millipedes, 

 worms and one snail. 



* Embody, G. C. & Gordon, Myron. A Comparative Study of Natural and 

 Artificial Foods of Brook Trout. Transactions Amer. Fisheries Soc, Vol. T»4, 

 pp. 185-200, 1924. 



