. ( 3G ) 



to the construction of this weir, extended over 80 or 100 

 miles of the river, instead of its being concentrated, as it 

 were, on a single spot. The fishing decreased until a breach 

 occurred, when it almost locally ceased, owing to the fish 

 being able to obtain access to their breeding- grounds, and 

 not being stopped by the weir, and they were taken even 

 above Trichinopoly. It decreased, doubtless due to the fish 

 being unable to breed : the year after this breach, when it 

 had been repaired, a great increase was observed in the fish, 

 evidently due to one season's breeding. Fruitless to deposit 

 their eggs below these constructions, when between the sea 

 and their spawning beds, and unable to pass them, extermina- 

 tion in such rivers will only be a question of time, should no 

 remedial measures be adopted. This fish never breeds in 

 tanks or canals. Amongst the predaceous sea fishes which 

 are migratory, a large sea perch, Lates calcarifer, ascends 

 sometimes hundreds of miles up large rivers as the Irrawadi, 

 pursuing the shad. Sharks, Carcharias Gangeticus, and saw- 

 fishes, Pristis, also ascend high up rivers, and a favourite 

 resort for them is below weirs, where they find ample means 

 of subsistence in the shoals of fish detained by those 

 structures. 



THE FRY OP FRESH- WATER FISH. 

 LIT. The immature or the fry offish,wliere they are 



Try of fresh-water fishes. found > and tlieir meanS f SUDSlst- 



HOW, instead of being protected, ence, and opportunities of growth, 

 they are destroyed. aTe questions which it is very material 



to offer a few remarks upon. I have already observed (para. 

 XLVIII) how the fry of fishes are protected from their voraci- 

 ous parents in hill streams and rivers, by those localities being 

 generally unequal to the supply of food for the mature or 

 large fish, which migrate up these water-courses in order to 

 deposit their ova : consequently, they drop down again into 

 the rivers of the plains as the waters begin to subside, leaving 

 the fry to descend with the next year's rains. These fry, 

 however, appear to likewise continue their descent in a very 

 quiet and gradual manner, but when they have an oppor- 

 tunity of going down-stream, they avail themselves of it. 

 In the Himalayas numbers of these young fish descend into 

 the kools or canals for turning mills (see para. XXII), where all 

 are captured. Those which reach pools in these streams appear 

 to often continue there throughout the dry months, unless des- 

 troyed, until the monsoon recommences. In the low country 



