PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1932 563 

 SPECIAL DISTRIBUTION TRUCKS 



For over a year the bureau has operated several units of the special 

 type of oxygen tank distribution trucks. These are now manufactured 

 and sold as complete units, and are used by a number of the States and 

 by various private fish culturists. The bureau's experience with such 

 equipment, on the Pacific coast and elsewhere, leads to the conclusion 

 that mider certain conditions it will meet distribution requirements 

 and render efficient service. 



EFFECT OF WEATHER ON SOUTHERN POND STATIONS 



During the earl,v part of March a period of exceedingly severe 

 weather was experienced over the greater part of the United States. 

 The effect of these storms and unseasonably low temperatures was 

 reflected in the reports from the bureau's southern pond stations, the 

 majorit}" of them recording the loss of all bass spawn which had been 

 deposited. It is especially noteworthy that stations located at widely 

 separated points were subjected to the same weather conditions. 



REARING OF GRAYLING 



The Pittsford (Vt.) experimental station is now rearing a second 

 generation of domesticated grayling. Heretofore it has been the 

 commonly accepted opinion among fish culturists that it was not 

 practicable or hardly possible to rear grayling even to the fingerling 

 stage. However, the lot of fish referred to was successfully brought to 

 maturity under artificial conditions at the Pittsford station, and eggs 

 in considerable numbers were taken from them and hatched. The 

 resulting fry are now being reared with the same measure of success 

 that attended the hatching of the parent fish. 



ERADICATION OF FURUNCULOSIS 



When a trout hatchery has become infected with the furunculosis 

 disease it has been the practice in too many cases to accept the 

 difficulty as one which can not be surmounted, and to trust to luck 

 that it will either die out naturally or that its ravages will prove 

 sporadic. Recent experience at tw^o of the bureau's stations has shown 

 that it is quite practicable by the adoption of rigorous measures to 

 eliminate all traces of the disease. Several years ago at the Barneveld 

 (N. y.) substation and during the past year at the Manchester 

 (Iowa) station a program of pond disinfection and other measures 

 appears to have eliminated the infection as an active factor in fish- 

 cultural w^ork. The experience at these stations indicates the necessity 

 for the adoption of heroic treatment, accompanied by a willingness to 

 sacrifice infected fish, equipment, and material. In other words, the 

 entire plant must undergo a complete overhauling from the water 

 supply source throughout the entire system of ponds, troughs, and 

 other equipment used. 



NEW FORM OF POND CONSTRUCTION 



Circular trout ponds of a new type are being constructed in con- 

 nection wdth the development of several of the new stations, and as 

 circumstances and funds permit ponds of the same design will be 

 installed at the bureau's older stations. All reports received on this 



