NOTES ON PISHES OF THE DELAWARE RIVER. 827 



course not the sea-fish so named by most people, but the common river- 

 chub {Semotilus rhotheus). I am inclined to think that this species, too, 

 is on the decline. Sturgeon are yearly decreasing in numbers, and I 

 doubt not, if nothing is done to prevent it, will soon become as scarce 

 as the " gar" {Lepidosteus osseus), which was formerly very abundant. 



In conclusion, allow me to make a few remarks with reference to the 

 ordinary habits of fishes, and to some supposed changes that have taken 

 place in the course of two or more centuries. 



Probably to a much greater extent than has been supposed, all fishes 

 are nocturnal in their habits ; and even those that move freely about 

 during the day are even more active at night. Either by an arrange- 

 ment of the eye, as in the nocturnal owls, or by some other sense, 

 they have the ability to move with the same rapidity when it is, to 

 men, " pitch dark, " as in the brightest sunshine. By a series of experi- 

 ments, made with traps of different kinds, I found that even our small 

 sun-fish, on the darkest nights, moved freely about and readily took the 

 hook, if properly baited. Cat-fish are all genuine "owls," and from 

 fykes kept constantly in position, 93 per cent, more fish were taken 

 between sunset and sunrise than between early morning and evening. 

 This does not apply simply to twilight and dawn; but on dark nights, 

 when I could distinguish nothing a dozen feet>off, not only perch, but 

 cat-fish, and the Cyprinoids generally were darting through the water. 



This night study of fishes brings two species prominently into notice, 

 the economical value of one of which is really considerable. I refer to 

 the common eel {Anguilla actitirostris) and the lamprey {Fetromyzon 

 americanus, Lesueur). Both of these fishes are exceedingly abundant 

 in the Delaware and its tributaries, and of much interest, the one as 

 an excellent article of food, the other as a great destroyer of the ova of 

 other fishes. 



The eel, abundant in every stream of water, mill-pond, and meadow- 

 ditch, as well as the river itself, is worthy of far more attention as a food 

 food than it has received; for itappears,judgiugfrom the annual reports, 

 to have been largely overlooked by the State Commissioners of Fisheries. 

 From long observation, I am disposed to acquit them of the charge of 

 destroying large quantities of ova of other fishes. So far as I can de- 

 termine, their food is of a varied character, and while a mass of eggs 

 would not be passed by unheeded, they do not appear to hunt them up, 

 or follow breeding fishes to their spawning beds. This latter habit, 

 however, I am fully satisfied, is a characteristic habit of the lamprey. 

 This fish, which is found occasionally hibernating in the soft mud at the 

 mouths of some of the inflowing creeks, appears to come from the bay 

 or ocean, (at any rate from the lower portion of the river,) in immense 

 numbers early in March, and remains about the rocks at the head of 

 tide-water for some time, as though waiting for the coming shad and 

 herring. With the shad they pass up the river beyond tide-water, and 

 in the rapid, rocky portions of the river, having deposited their own 



