428 Lake Maxinkuckee, Physical and Biological Survey 



becomes rather warm and foul in the summer or early fall and in 

 which the fish are crowded. The presence of the parasites is 

 usually only temporary and need cause no particular annoyance, 

 and none whatever, if the parasites escape observation. 



The spawning time of the Yellow Perch is early in the spring, 

 soon after the ice has disappeared. The egg-masses are among 

 the most remarkable among those of freshwater fishes. The spawn 

 is in a single piece or mass, a "much-elongated ribbon-like structure, 

 of a semi-transparent light grayish color. One end, corresponding 

 to the anterior part of the roe, is larger than the other, and is 

 bluntly forked. The spring is very long, but may be compressed 

 lengthwise by virtue of an arrangement into regular transverse 

 folds like the sides of a bellows or accordion. When deposited the 

 eggs are in a loose globular form, and after being fertilized and be- 

 coming 'water-hard', their mass rapidly becomes many times larger 

 than the fish which laid them. The length of the. strings is from 

 2 to more than 7 feet, depending on the size of the fish. One fish 

 in an aquarium at Washington deposited a string of eggs 88 inches 

 long, 4 inches wide at one end and 2 feet at the other, whose 

 weight after fertilization was 41 ounces, while the weight of the 

 fish before the escape of the eggs was only 24 ounces. 



A cavity extends the whole length of the egg mass, its walls 

 being formed by the delicate membrane in which the eggs are em- 

 bedded. The cavity is almost closed, small apertures occurring 

 irregularly, which have the appearance of being accidental, but 

 may be natural, in order to permit the circulation of water on 

 the inside of the mass. 



The egg-string is quite light and resilient or springy, the 

 least agitation of the water causing a quivering motion of the 

 whole mass. 



The diameter of the egg is 1/13 inch. The quantity can not 

 be easily measured, but the number is approximately 28,000 to a 

 quart. 



Head 3.25 ; depth 3.25 ; D. XIII to XV, 13 to 15 ; A. II, 7 or 8 ; 

 scales 7-74 to 88-17, 54 to 62 with pores ; back highest at origin of 

 spinous dorsal, which is more or less behind insertion of pectoral ; 

 profile convex from dorsal to occiput, thence concave anteriorly, 

 the snout projecting, a little longer than eye; mouth somewhat 

 oblique, maxillary not quite reaching opposite middle of orbit ; gill- 

 rakers x -(- 15, the longest -J to length of branchial filaments ; 

 cheeks closely scaled throughout, the scales imbricated; opercular 

 striae and rugosities on top of head well marked; first anal spine 

 longer than first dorsal spine; first dorsal spine inserted above 



