WHITE SUCKER 
151 
surface of the water was broken by the splashing of the whole group. This lasted 
but a few seconds, whereupon the female retreated into deeper water downstream. 
In five minutes she returned, and the spawning was repeated, though this time she 
stopped not over 15 feet from where the observer was stationed. 
That the dates given above for Beebee Lake can not be taken as applying to other 
habitats about Ithaca is evidenced by the fact that in streams accessible to suckers 
from the colder waters of Cayuga Lake breeding continues much later. Estimated 
dates when eggs were laid in such streams run as follows: Mouth of Taghanic Creek, 
May 25; mouth of Six Mile Creek, June 4; the inlet above Buttermilk Creek, June 9; 
mouth of Trumansburg Creek, May 25; mouth of Butternut Creek, June 25, and 
lower Salmon Creek, June 4. These dates were obtained by computing back from 
the date when fry of a determined length and age were collected. For example, if 
fry 18 millimeters in length were taken as late as August 10, we arrive at the spawn- 
ing date by subtracting the age, in days, of such fry — viz, 45 days — from the date of 
capture, giving us June 26. From June 10, throughout the summer, collections were 
made twice or three times a week, which gave ample opportunity to learn of the 
average size of fry in the various streams. 
This method is open to error, of course, as the basis for the computation of age 
was made upon eggs and fry raised under slightly unnatural conditions. However, 
the estimate is probably close to the truth and seems to indicate that suckers in the 
warmer, shallower, upland streams breed considerably earlier than those coming up 
out of the colder water of Cayuga Lake. Averages give us May 6 as the approximate 
close of spawning in the upland streams and June 5 for six streams accessible from the 
lake. These streams differ in temperature within the two groups here contrasted, 
which would alter the rate of develpment in each case, yet the difference of a month 
between the spawning in these two types of streams points to the coldness of the 
lake as the cause of the delay. 
While no ripe females were taken in any habitat before April 27, it is of interest 
to note that ripe males were taken as early as March 23. One taken on that date, 6^2 
inches long, was so ripe that the milt flowed on handling the fish to remove it from 
the trap. A male taken February 7 was so nearly ripe that spermatozoa removed 
by dissection were active when placed in a drop of water. 
Probably the white sucker does not breed until at least 6 inches in length. 
They are 4 or 5 years old at this size, and upon most sucker scales the circuli then 
formed show peculiarities, to be described later on, which doubtless register the 
physiological activities peculiar to spawning. For a clear account of the breeding 
behavior the reader is referred to Reighard’s excellent paper (1920). 
That the pearl organs of the males of this species are effective to roughen their 
sides and render the escape of the female difficult is witnessed by the fact that females 
taken from Beebee Lake after spawning showed their sides quite denuded of epi- 
dermis, the scales being bare from the caudal to the dorsal fin. Here we have one 
case of true effectiveness of these problematical structures, the pearl organs, though 
it seems doubtful that a use can be found for them as they occur on many of the 
Cyprinidse. 
