PROPAGATION AND DISTRIBUTION OF FOOD FISHES, 1923. 83 



the losses that have occurred recently were unsuccessful, and in the 

 face of a shortage of nearly 200 breeders two of the ponds were 

 allowed to remain idle. The bass work was still further curtailed 

 by a total lack of results in two other ponds that had been stocked 

 with adult bass transferred early in the spring from Washington, 

 D. C. Notwithstanding these discouraging factors, however, the 

 station's production of fry and fingerling fish of this species ex- 

 ceeded last year's by 140,000, while the total output of the station 

 and its Harris Pond auxiliarv was nearly two-thirds larger than that 

 of the fiscal year 1922. 



Early in the year the pathologist made an effort to discover the 

 cause of the heavy mortality occuring among the adult bass. No 

 conclusion was arrived at, but it is the belief of the station super- 

 intendent that it is due to some deficiency in the food supply. 

 Chopped mullet constituted the food supply of these fish during the 

 year, and while the losses have been lighter than last year when 

 beef heart was being fed to them, the mortality has, nevertheless, 

 been much heavier than at other stations where the hearts are gen- 

 erally employed as a food for brood fish. 



The year's production of crappie was almost negligible, only 1,500 

 fingerling fish being realized from one half-acre pond. For some 

 unknown reason this species has never responded satisfactorily to 

 artificial propagation at the Bullochville station. 



Past experience at this station has demonstrated that ponds con- 

 taining water throughout the year or remaining dry for only two 

 or three months during the year are apt to produce large numbers 

 of such injurious insects as Dytiscus, Gyrinidse, and Hydracarina. 

 With this in mind it was decided to drain all ponds immediately 

 after completing the distribution in the late summer of 1922 and 

 allow them to remain empty until late in February. Apparently 

 this change was very beneficial. Not only were undesirable insects 

 unusually scarce during the spring, but the ponds contained more 

 daphnids, cyclops, chirinomids, and other natural food for young 

 fish than ever before. 



As the water from Cold Spring has always been pronounced too 

 deficient in lime for the best results in fish-cultural work, an experi- 

 ment was started in September with the view of ascertaining if this 

 defect might be overcome by introducing lime in the supply. In a 

 box 4 feet square and 2 feet high a false slat bottom was inserted, 

 1 inch of space being left below the slats. This was placed in one 

 of the ponds, a layer of coarse gravel distributed over the slats, a 

 2-inch layer of sand over that, nnd finally a barrel of freshly slaked 

 lime. A three-fourths-inch pipe was then installed in such a way 

 as to force water up from beneath the slats and cause it to flow evenly 

 through the gravel, sand, and lime into the pond. On May 1 when 

 the box was removed it was found that all the lime had dissolved. 

 As the results attained in this pond during the succeeding spawning- 

 season were not distinguishable from those in the untreated ponds, 

 it is evident that the experiment had no beneficial effect upon the 

 water supply. 



In the course of the year Cold Spring, the main source of the 

 station water supply, was covered with a shingle roof supported 

 on 8-foot studding set in concrete blocks. The exclusion of leaves 

 and debris was accomplished by inclosing the studding with wire 



