only from the States of Illinois, Indiana and Iowa. This may have 

 produced some bias in the returns. Moorman (1956) found in a study 

 of 60 ponds in Iowa, that ponds less than 0.5 acre were usually less 

 successful than ponds between O.5 and 1.0 acre. Swingle (l9^9) 

 reported that unfertilized ponds of less than O.5 acre and fertil- 

 ized ponds of less than 0.25 acre are too small to insiire good 

 results with the bass-bluegill combination. 



Ponds stocked with bass in the spring of 1957 were employed in 

 the survey because these ponds would experience their first full 

 year of fishing in 1959* In northernmost latitudes, a few ponds 

 stocked in 1956 were used so that the fish in all ponds would have 

 had sufficient time to reach a size permitting angling. Nearly all 

 the ponds had received bluegill prior to the introduction of the 

 basB. In the Southeast, redear sunfish are stocked in combination 

 with bluegill, and channel catfish were stocked in 155 ponds in the 

 Southwest. Fish were provided on the basis of a completed applica- 

 tion, which had been reviewed in most instances by the locsil SOS 

 representative, and approved by State conservation officials, as 

 well as by the Bureau. The fish were stocked as small fingerlings. 

 The rate of stocking varied: bass at rates from 50 to 100 per acre 

 and bluegill (including redear sunfish) at rates from 100 to 1,000 

 per acre. 



Four regional offices of the Bureau, located at Albuquerque, 

 Atlanta, Boston, and Minneapolis, were each assigned a number of 

 ponds to report, based on the ninnber of applications for warm-water 

 fish which were filled by them in 195?. The States of the Pacific 

 Coast and the more northern States were omitted, because of the 

 small number of ponds stocked with warm- water species and the diffi- 

 culties of midwinter travel. In all, 25 States were included in the 

 survey . 



Ponds were chosen on a systematized basis, with the interval 

 derived from the ratio between the total number of applications 

 for bass filled in 195T> divided by the number of reports desired. 

 Within this interval the first pond was selected at random, with 

 subsequent ponds chosen systematically. This method was followed 

 with few exceptions. 



A list of alternate ponds, chosen in the same manner, was also 

 prepared in each regional office, so that should it be impossible 

 to obtain a report on a particular pond, an alternate chosen in the 

 same manner could be substituted. As field work on the survey was 

 conducted during the month of January, conditions of weather and 

 rural roads made this feature necessary. Alternate ponds made up 

 approximately 10 percent of the sample. 



