Shir a. — Fish Culture at the Fair port Station 43 



the hatch represents a clear gain as the eggs would otherwise 

 have been lost. The total cost of hatching and planting the fish 

 the past season was slightly more than seven cents per thousand, 

 including over-head expenses and the salaries of permanent 

 employees actually engaged. It may be safely said, then, that 

 the work is now on a practical and well established basis. 



In view of the increased demand for additional cheap food 

 fishes to supplement the meat supply of the country and aid 

 in reducing the high cost of living, experimental hatching of the 

 European Carp, Cyprinus carpio, in jars was undertaken this 

 spring. Approximately 112,000 fry were hatched and liberated 

 in the Mississippi River. Several thousand reserved for additional 

 experiments, were placed in one of the ponds and a very marked 

 growth has been made. 



Some work was also done last year on the Missouri Sucker, 

 Cycle phis elongatus, and 83,000 fry hatched in jars were planted 

 in the Mississippi River. This is a very good food fish and com- 

 mands a price almost equal to that of the buffalofish. 



(c). Studies of Natural Food. — No work in pond-fish culture 

 would be complete without a thorough knowledge of the natural 

 food taken by the fish under varying conditions. This information 

 is being obtained by intensive food studies carried on by both 

 regular and temporary employees. Weekly collections of young 

 fish are made from each of the ponds throughout the summer and 

 fall for food examinations and the kind and quantity of food taken 

 is compared with the available supply in the pond. Interesting 

 and valuable data, indeed, are being accumulated. For instance, 

 we have found that the very young buffalofish subsist largely 

 upon rotifers which are taken in large numbers, later turning to 

 Chironomus and other insect larvae and Entomostraca. The 

 stomach examinations reveal the fact that all the young fish feed 

 generally and with but little discrimination on the prevailing 

 food of the ponds, as the proportion of the various items con- 

 stituting their diet are comparable to the proportionate abundance 

 of their occurrence in the ponds. These studies also serve as an 

 index of the food required for optimum growth. A few examina- 

 tions made last year indicate that it is desirable to continue 

 making the collections to some extent throughout the winter so 

 that more complete data will be at hand. 



