426 Roosevelt Wild Life Annals 



. . . Close exaiiiination of the egg-lobe revealed the existence of an interior 

 passage throughout its length. The inner cavity was almost entirely closed, being, 

 however, slightly open to outside communication by means of occasional small 

 apertures in the walls. These openings were so unimportant in size and number 

 and of such irregular shape and occurrence that they were at first regarded as 

 accidental. Commissioner McDonald, however, suggested that they formed a part 

 of the system of natural circulation and therefore were probably essential to 

 aeration, and further exaniinatinn tended to support the view. The egg-lobe was 

 characterized by great springiness, being in fact so highly vibratory that the least 

 agitation of the surrounding water put the whole in motion. This movement evi- 

 dently forces the water out and in, and hence the apertures seem to be a part of the 

 design, which is a variety of pumping apparatus, for throwing out the stale water 

 and taking in fresh supplies." The explanation is very plausible, and we see here 

 probably another method of aeration of eggs which may be compared with the 

 fanning action employed by centrarchids resting over eggs in bowl-shaped nests. 



The hatching time for the Perch eggs is 27 days, according to Leach ('27. 

 p. 21), at a temperature of 47° F. 



In July, in Oneida Lake, large schools of the young of the year api)ear in 

 shallows and at this time are about i to 2 inches long (Nos. 522, 552, 591). By 

 August and September these young are about 2>^ inches long, and the next sum- 

 mer, when perhaps 14-15 months old, they are near three inches in length. It ap- 

 pears from our collections that Perch grow to about 23^ inches the first year, but no 

 critical study of the growth was made. Harkness ('22, p. 91 ) made a growth study 

 of young Perch in Lake Erie, finding them at 6 months to be 2 inches, and at 

 18 months, 4 inches long. Embody ('15, p. 227) gives the following growth data 

 for the Perch: 5 months, 2_!/^ in.; 12 months, 3-4 in.; 2 years, 6-7 in. Here also 

 the growth of the young Oneida Lake fish appear to be about the same as given by 

 Embodv. Rolen ('24. p. 308) obtained data on the growth of Perch in Winona 

 Lake, Indiana, witli the following results ; 



_>3 fish, I year old, average length about 3 inches 

 31 fish. 2 years old, average length about 4j4 inches 

 ii> fish. 3 years old, average length about 5^ inches 



The mature fish vary consiilerably in size. Pearse and Achtenberg ("20, p. 

 339) note that in a sni.ilKr lake they become mature at a smaller size than in a 

 larger one. In Wisconsin lakes (I.e.) Perch mature in about two years. At the 

 spawning time males precede the females to shallow water (I.e., pp. 2\-7- o.S')^ : 

 and there are more males than females. Perch as caught by anglers are commonly 

 under a foot in length and weigh less than a pound (Forbes and Richardson, '09, 

 ]j. 277). In some lakes l^erch of two pounds or more are common. The largest 

 Perch ever taken, according to Nichols and lleilner ('20, p. i"), weighed 4 llis. 

 yA oz. 



Habitat. Perch seem lo inhabit all |iarls ol < »nrida Lake, the larger ones m 

 deeper and the .smaller ones in shallower water, with the very smallest in the 

 marginal shallows. Persons who fish for I'crcli in inland lakes observe quite a 

 close relation between size of fish and dejith oi water. Ilankinson. who has fished 

 for Perch in nianv lakes in Miclii-an. finds that in w.atcr about (wv to ten feet deep 



