G6 U. S. BUREAU OF FISHERIES. 



TUPELO (miss.) station. 

 [David Davies, Superintendent.] 



The output of this station for the year consisted of 405,500 large- 

 mouth black bass, 73,005 sunfish, and 1,280 crappie, and the distribu- 

 tion was extended to approximately 310 applicants, located in Mis- 

 sissippi, Alabama, Tennessee, Arkansas, Louisiana, and Kentucky. 

 The station output ^ras also supplemented by a carload shipment of 

 miscellaneous fishes from the rescue field on the upper ISIississippi 

 River, consisting of crappie, catfish, rock bass, buffalofish, carp, and 

 yellow perch, all of which entered into the general distributions. 



Of possible interest in connection with pond fish culture was the 

 unusually late spawning of the largemouth black bass this year. 

 On August 19, 1921, a lot of 3,000 advanced largemouth black-bass 

 fry were taken from one of the station ponds, and again, on Sep- 

 tember 28, another lot of the same species and size was obtained. 



PRACTICAL DEVICES FOR USE IN POND FISH CULTURE. 

 A PR.VCTICAL SYSTEM OF CLEANING FISHPONDS. 



The necessity for the frequent cleaning of ponds in which fish 

 are retained under artificial conditions is well known. If the ponds 

 are of cement or lumber construction, the usual method of cleaning 

 is to lower the water level and scrub the sides and bottom of the pond 

 with a suitable brush. During the cleaning process the water in the 

 pond becomes turbid and polluted from stirring up the accumulated 

 sediment and filth from the bottom of the pond. The fish are forced 

 to endure tliis unnatural condition until the pond is scrubbed, the 

 accumulation of sediment flushed out through the outlet, and the pond 

 again filled with clear water. In addition to this unfavorable condi- 

 tion to which the fish are exposed they are subject to further possible 

 injury by bruises from contact with the brushes used in the scrub- 

 bing process. These conditions are entirely unavoidable under the 

 system of cleaning in general use. 



At the Manchester (Iowa) station a system of cleaning ponds that 

 successfully overcomes both these difficulties has been adopted. (See 

 Fig. 2.) At this station there are eight stock ponds of cement con- 

 struction. They are approximately 80 by 13 feet and are 3 feet deep 

 at the outlet, the bottom sloping upward toward the inlet, where the 

 depth is 2-^ feet. 



For the proper cleaning of the ponds a cement wall or dam, ex- 

 tending into the pond 4J feet from each side, is installed, leaving a 

 4-foot opening in the middle. This dam is placed 20 feet from the 

 inlet end of the pond and is 1 foot high. The open ends are 

 grooved to accommodate a dam board 2 inches in thickness. In 

 cleaning the pond the Avater level is lowered until that portion of 

 the pond bottom between the inlet and the division wall is just cov- 

 ered. The pond Ijeing deeper at the outlet end, there is still sufficient 

 water to hold the fish safely while the other section of the pond is 

 being cleaned and flushed. After cleaning the first section the water 

 is permitted to rise until the division wall is about submerged. The 

 fish are then driven through the 4-foot opening in the wall into the 

 clean section of the pond by the use of a " push screen." A board 



