400 



5- Swales, among willows and "buck brush" ; water 4 to 5 feet, 

 191 1 ; too deep for rooted aquatics; occasional Ceratophylluui. Flag 

 Lake Swale. 



ESTIMATED NUMBERS SPAWNED, HATCHED, EUNGUSED, AND MATURING, 

 DANHOEE's FIEED (600 acres), I9IO 



Number of eggs present May 9, 1,451,818,500. 



Per cent, of eggs with eye-spots May 12, ten. 



Per cent, of fungused eggs in field (to beginning of hatching), 

 ninety. 



Number of eggs hatched, 145,181,850. 



The percentage of eggs fungused in the north end of Danhole's 

 field in May, 191 1, was much greater than in 1910, probably equaling 

 98 or 99 per cent. This high ratio was probably due largely to the 

 abnormal lowness of the water and unseasonable warm weather. 

 Both in 1910 and 191 1, Danhole's field contained a great deal of rot- 

 ting dead grass and flag. In laboratory lots it was noted that eggs 

 hatched better in jars containing fresh living algae and Ceratoph\llum, 

 and free from dead grass and trash. Eggs spawned in Ceratophylluui 

 in Sangamon Bay, May, 191 1, showed a relatively small ratio of fun- 

 gus, probably less than 25 per cent. 



H. M. Smith (quoted in Fishing Gazette, June, 1910), has ex- 

 pressed the opinion that one out of a thousand salmon hatched comes 

 to maturity. On this basis, out of 145,181,000 carp hatched in Dan- 

 hole's field in May, 1910, 145,181 would reach maturity, and it would 

 take only 28 times this number to replace the annual take-out of carp 

 from the river by fishermen (about 20,000,000 lbs. for the whole 

 state in 1908, at an average weight of 5 lbs. each, equivalent to 

 4,000,000 adult carp). In other words, it would take only 28 marshes 

 the size of Danhole's field to replace the present annual catch on the 

 basis of one out of a thousand hatched reaching maturity. The ratios 

 actually realized in seasons of favorable water-levels are probably 

 much better than this, both in per cent, hatched (after deducting for 

 fungus) and in per cent, of fr\ that reacJi maturity. 



HABITS AND EOCAI, PREFERENCES OF FRY AND FINGEREINGS 



I. Marked preference of fry for animal food. — Specimens ^ to 

 ^ inch long from Danhole's field, June 3, 1910, had eaten large quan- 

 tities of Cyclops, Alona, and an ostracod, with a trace in some cases 

 of Spirogyra. One had eaten nothing but large Cyclops. A specimen 

 lyi inch long from the head of Liverpool Lake, July, 1910, had 



