BULLETIN OF THE UNITED status fish commission. 283 



83.— RAISING CAKP IN BICE-FIB !.»«. 

 By K. .1. DONALDSON. 



[From •! letter to Prof. 8. F. Baird.] 



I have the lienor to report the result of my experiment with German 

 carp in a rice -field. I drained it today and cleared it of fish. The re- 

 sult is extraordinary as to growth of fish, but a failure as to numbers. 



Last April I received from you 20 breeding fish. 1 had prepared the 

 10 acre field by rilling up the main drains, except about 100 yards of 

 one of them. I now believe this had better not be done, but that the 

 fields should be left as they are for raising fish. Spawners should be 

 provided for differently. The field had an ordinary rice field trunk, 

 which I incased on the inner side with a frame 8 feet square, one side of 

 which had galvanized wire screen with oue eighth of an inch mesh. The 

 gate was so arranged as automatically to reduce the water 4 inches and re- 

 fill twice a day. All the fish were supposed to be removed. In this pond 

 the carp were put ; but two of them were sick when received, and after- 

 wards died. The growth* of grass and water-plants in the pond was all 

 that could be desired. A man was placed in charge of the field, whose 

 duty was to keep off fish-hawks, cranes, snakes, &c, which are very 

 plentiful here. Vast numbers of frogs found their way into the pond 

 during the spawning season. 



We found evidence during the summer of 6 large carp being destroyed, 

 which, with the 2 previously mentioned as dying, would leave only 12 

 breeders; others might have been destroyed without our knowledge. 

 During the spring hundreds of little fish were taken from the outside of 

 the screeu, where they had been killed by the force of the water press- 

 ing them against and into the screen. They were eels, trout, and that 

 class offish which abound in our waters. 



During the summer we had a visitation of salt in our rivers, and not 

 having full faith in your statement "that it would not injure carp, as 

 they would adapt themselves to it," I was afraid to risk it, and so shut 

 out all water. After three weeks a leak occurred in my trunk, and the 

 water gradually left the pond until it was very low and becauie quite 

 warm. The water still continued salt in the river, and I dared not use 

 it. During this time numbers of beautiful fish were seen swimming in 

 the drains, as the water was now in the drains alou<>, the surface of the 

 field being uucovered. These, from their graceful appearance, I thought 

 were carp. At this time a series of extra high tides set in, with a north- 

 east wind, and the salt water, which I would not let in, came over tin; 

 hanks in such quantities as to make the little water remaining in the 

 pond rather salt. If 1 had allowed the gate to continue taking in its 

 usual flow on a full field, the salt, in all the time it continued, could not 



