xl EEPORT OF COMMISSIONER OF FISH AND FISHERIES. 



the rocks and attempting to climb over tbeir surface as by any otlier 

 feature, the numbers to be seen being simply incalculable. 



After reaching a suitable place of abode, in fresh water, the eels 

 remain, as is supposed, for at least tliree years, growing to a considerable 

 size. After becoming sufficiently mature, their instinct, probably that 

 of reproduction, carries them seaward again during the autumn ; and 

 it is at this time that various forms of flsh-dams and fish-weirs are called 

 into requisition. The simplest kind consists of two lines of stone wall, 

 forming the sides of a rude dam, made so as to converge and bring 

 the angle down stream, through which the passing water falls into 

 a sort of basket. This consists of a frame with lattice- work at the bot- 

 tom, so arranged that, while the water passes through, the fish are forced 

 up over the slats, arranged so as to form a series of slides, and fall into a 

 receptacle beyond, where they are taken sometimes by wagon-loads. The 

 most productive result of this mode of fishing consists of eels inter- 

 cepted in their seaward movement, although other fish are often taken. 

 It is very destructive to young shad and is very properly interdicted by 

 the laws of Pennsylvania and New Jersey, in their shad-rivers. 



The laying of the eggs, it is supposed, takes place in the autumn, or 

 winter, and the young begin to move up in the spring, or early summer. 



In further reference to the history of the eel, we may state that its 

 precise mode of copulation and of reproduction was entirely unknown 

 until recently, but that at the present time the view is maintained by 

 very high authority, principally that of Italian physiologists, that the 

 eel is strictly a hermaphrodite; that is to say, that both the male and 

 female organs are found in the same animal. These are said to be 

 developed to the proper degree in winter, and the eggs discharged from 

 the ovary are fertilized by the seminal fiuid from the testicles, and leave 

 the body in a condition for further development. 



18. — DIFFERENT METHODS OF MULTIPLYING FISH. 



We have already indicated in the previous remarks some of the 

 principal methods devised for increasing the number of fish in a given 

 locality, but it may be well to refer again to this in a more systematic 

 manner. Capturing fish in one locality, and transferring them to 

 another, simply for the sake of greater convenience in securing them 

 when wanted, does not come under this head. The fish-ponds of the 

 ancient Eomans, and the floating boxes or cars in which living fish are 

 kept by fish-dealers, belong essentially to the same category. As far as 

 the actual multiplication of fish is concerned, we have to deal especially 

 with four principal methods. 



The first, and simplest, consists in transferring fish of both sexes, 

 whether still young and requiring further growth, or fully mature, and 

 •especially at about the period of their spawning, from one locality to 

 another, where they can make themselves at home, and in due coiu'se of 

 time increase and multiply. 



