The fish were fed a floating catfish ration at the rate of three 

 percent of body weight per day. After 23 days there was only 0.001 

 pound (0.45 gram) difference in the average weight increment made 

 by individual fish in the two populations, indicating similar grow- 

 ing conditions in the two sections of the pond. 



In order to establish differing densities in the similar 

 halves of the pond, two hundred fish were seined, marked (pectoral 

 clip) and transferred from the north to the south half. This pro- 

 vided 100 fish in the north half at a density of about 600 fish 

 per acre (1,433 fish per hectare), and 500 fish in the south half 

 at a density of about 3,000 fish per acre (7,413 fish per hectare). 

 We could now observe the influence of the crowding and could evalu- 

 ate the potential for the fencing technique. It might permit utili- 

 zation of a small section of a river or a reservoir, or other "wild" 

 waters for controlled catfish culture. Access to foods associated 

 with the natural bottom of a fenced-off area might allow use of a 

 less expensive feed than if the fish were confined in cages. 



Results . — Results of the draining census following a grow- 

 ing period of 100 days are shown in Table 1. Slightly smaller 

 average weights (0.25 lb. vs. 0.31 lb.) (114 grams vs. 139 grams) 

 and shorter lengths (9.6 in. vs. 10.1 in.) (24.5 centimeters vs. 

 25.7 centimeters) of individual fish in the most crowded popula- 

 tion indicated a small loss in efficiency, but rates of survival 

 were higher (96 vs. 91%) and rates of food conversion lower (1.38 

 vs. 1.43) in the most dense population. It therefore appears 

 that the effect of crowding was minimal, and probably not sig- 

 nificant at the time of termination, and that additional study of 

 the technique would seem justified. Table 1 made no distinction 

 between marked and unmarked fish, partly for sake of simplicity, 

 but primarily because there was no difference between marked and 

 unmarked fish in either survival or rate of growth. 



CHANNEL CATFISH FRY IN 1-ACRE (0 .4-HECTARE) PONDS 



Materials and Methods . — Channel catfish fry did not become 

 available in 1968 until late July, which permitted only a rather 

 abbreviated study. We decided to measure the success of stocking 

 fry in 1-acre (0.4-hectare) ponds at four different densities, and 

 to consider the value of providing supplementary feed at such small 

 sizes and relatively light densities. When stocked on July 25, 

 1968, the fry had an average length of about 1 inch (2.54 centi- 

 meters), and numbered 4,082 to the pound (8,999 to the kilogram). 

 The total stock of 38,000 fry was divided between four pairs of 



