110 ILLINOIS BIOLOGICAL MONOGRAPHS [110 



and this is repeated in other cisco inhabited lakes. In former years the 

 catches were much larger, 200 fine fish a day per fisherman being a fair 

 catch. A conservative estimate places the cisco catch in Oconomowoc lake 

 during the last 40 years at least as high as 1,000,000 fish! There has been 

 no restocking, for the cisco is not raised in any hatchery in the state. In 

 spite of the fact that the species is prolific, the fact remains that the rate of 

 growth is slow. The result of the enormous catch each year is that the 

 size of the fish has been reduced about four fifths! I have a record of thirteen 

 fish caught on March 3, 1908, that weighed over 4| pounds each; a 3 pound 

 cisco is still occasionally caught, but is very, very rare; dead fish are some- 

 times found during the summer that weigh upward of 4 pounds. But in 

 the winter of 1924 the average weight of 244 fish weighed by the writer 

 was just 116 grams — a little better than four to the pound! 



Until the last few years there were no laws relating to the capture of 

 the cisco in the inland waters of Wisconsin. Repeated pressure on the 

 state legislature finally placed a bag limit of 25 per man each day on the 

 species. But this is not sufficient. In view of the situation as it now stands 

 the writer recommends the following conservation methods, these being 

 well worth while as the species is a most excellent table fish. 



1. Cisco fishing in all lakes in Waukesha county should be closed for 

 a period of five years. 



2. A size limit of 12 inches should be established. 



3. The bag limit should be reduced to 15 each day. 



4. The cisco should be raised in the bass hatcheries during the winter 

 when these hatcheries are idle, and fry should be planted in suitable lakes. 



SUMMARY 



1. The cisco, Leucichthys ariedi, is a member of the family Salmonidae 

 and has a wide range in the deeper glacial lakes of the Mississippi valley, 

 particularly in the northern part. It is known to occur in fourteen lakes in 

 Waukesha county. 



2. It is a deep water species, inhabiting the deepest parts of the lake 

 during the winter, spring and fall. 



3. Spawning occurs in late November or early December, the deter- 

 mining factor being the temperature of the water. 



4. The males precede the females into the shallows, arriving when the 

 water cools to 4.3°C. The females arrive a few days later, with the tem- 

 perature dropping to 3.8°C, and spawning is at its height at 3.3°C. 



5. Males outnumber the females, there being a higher mortality among 

 the females during the warm water period of summer. 



6. The eggs develop in from ten to twelve weeks, depending on the 

 temperature of the water. 



