NOTES ON FISHES OF THE DELAWARE RIVER. 829 



the comparative abundance of this perch, inasmuch as I have frequently 

 ioiind two streams apparently alike, and not widely apart, maybe in 

 the one case filled with them, and in the other wholly wanting them ; 

 but if we compare their numbers with the non-auadromous percoids it 

 will be found not as abundant as the common sun-fish (Ichthelidw) with 

 which they are frequently associated. I have no means of determining 

 the maximum size of the yellow perch. A specimen caught in the Dela- 

 ware Eiver at Bordentown, Burlington County, New Jersey, in May, 

 1865, weighed 4 pounds o^ ounces. I have frequently met them weigh, 

 iug 1^ to 2 pounds. An average sized adult yellow perch, as found in 

 the Delaware River and the principal inflowing creeks, may be said to 

 be 9 inches in length and weigh from 6 to 8 ounces. 



The young perch, by November 15 of their first year, i. e., when six 

 months old, are about 2| inches long. Of their subsequent growth I 

 have not been able to determine anything positively, but believe it to 

 be rapid. It very probably varies with the abundance or comparative 

 absence of live food ; as in some ponds where cyprinoids are not 

 abundant the perch seem never to attain to large size. 



No distinctions of sex are noticeable in the smaller fish, i. c, of one 

 and two weeks' growth, either in the shape, dimensions, or.rate of growth ; 

 but when the full growth has been attained, or at least, the generative 

 functions become active, the females, early in the spring, are easily 

 known by their more prominent abdomens, and a duller tinting of the 

 yellow surfaces of the scales. The transverse bands are duller, and the 

 abdominal fins also have less of the brilliant carmine-color characteristic 

 of males, especially at this time of the year. 



On the approach of very cold weather — and it seems as if these as 

 well as all other fishes could foretell the state of the weather — the yellow 

 perch leave the shallower waters and congregate in deep holes, where 

 the water at the bottom appears to remain sufficiently warm for them. 

 Thus in December and January I have found a large number of them 

 in a deep hole — in the bed of a tide-water creek, of about one-half of 

 an acre in extent, and of an average depth of 20 feet. Such fish remain 

 throughout the winter in moderately good condition, are active and 

 in high color, although upon examination their stomachs prove to be 

 empty, or very nearly so. When found at this season (winter) and in 

 such a spot they will not take the hook, however baited.* 



In March, although there may be considerable ice still in the water, 

 floating or stationary, they will take the hook very eagerly, and from 

 that time until late in autumn are certainly a very "gamy" fish to cap- 

 ture. In May, when the female perch are heavy with ripe ova, they 

 will not take the hook very readily, although not as a rule refusing it; 

 but this critical season does not seem in any way to influence the habits 

 of the males. At this time the violent exertions of the fish, when taken 



*A friend assures us he has taken them iu midwinter from such holes when with 

 live bait he was fishing for pickerel. 



