REPORT OF COMMISSIONER OF FISH AND FISHERIES. 147 



no youug iudividuals having been observed. Moreover, the dead and 

 diseased fishes had been feeding almost excluvsively on a red insect 

 larva i^ecnliar to the nind of the deep water, while all the healthy fishes 

 observed had been feeding on shallow-water forms. 



The mortality, thus, seems to have been limited to the perch that 

 Avere ranging in the deeper parts of the lako'iu company with the dis- 

 eased herring, and observations indicate that such a deep range for 

 the perch is unusual in midsummer. There also seems to be a deficiency 

 in Lake Mendota of the kinds of animals usually selected by the perch 

 as food, according to observations made elsewhere. A heavy flooding 

 rain which occurred not long before the outbreak of the disease may 

 have washed into the lake unusual quantities of organic matter from 

 the swamp beyond Catfish Bay and from the surrounding country. 

 Quite similar cases of destruction of the native fishes are of rather 

 common occurrence in the rivers of Illinois in the hottest weather of 

 the year. They usually, if not always, follow upon flooding rains, and 

 thus occur when the streams are full or overflowing with turbid water 

 loaded with the products of decay. 



During the summer of 1890, Prof. 0. Dwight Marsh, of Eipon Col- 

 lege, began a physical and biological examination of Green Lake, 

 situated in Green Lake County, Wis,, for which the Fish Commission 

 supplied one of its deep-sea thermometers for taking bottom tempera- 

 tures. His investigations will be continued during the summer of 

 1891, when he expects to publish an account of his results. 



INDIANA. 



The investigations begun in Indiana by Prof. B. W. Evermann in 

 1888 were continued by him during the summer of 1890 in the northern 

 and western parts of the State. Considerable work was done at inter- 

 vals in the vicinity of Terre Haute, both in the Wabash Eiver and in 

 the numerous ponds which occur along its course in this region. Dur- 

 ing the regular spring rise in the river these ponds fill with water and 

 numerous fishes enter at the same time, but in the summer and early 

 autumn many of the ponds become dry, and great numbers of fishes 

 perivSh there in consequence. Among the species which are thus de- 

 stroyed are the black bass and crappie, and other valuable food-fishes. 

 Several hundred specimens in good condition were transplanted to 

 Lake Maxiukuckee by I'rof. Evermann. Observations and collections 

 Avere also made at Bonebank and Mackey Ferry on the lower Wabash 

 River and at several places in the St. Josei)h River basin, as follows: 

 Pigeon River, Twin Lakes and Cedar Lakes near Ontario and Lima; 

 Oliver Lake at Valentine, and Elkhart River at Goshen. Material 

 was likewise obtained at Plymouth from the Yellow River, a tributary 

 of the Kankakee, from Lake Maxiukuckee, and from the Tippecanoe 

 River, a few miles vsouth of the lake. Prof. Evermann was assisted in 

 his work by a number of his students at the State Normal School, Terre 



