338 Intinois NATURAL History Survey BULLETIN Vol. 26, Art. 4 
Table 4.—Data (from table 12) on catches of wing nets of two different mesh sizes used 
in fisheries survey of the Caruthersville-Dubuque section of the Mississippi River, 1944, the data 
selected and presented to allow comparison of the efficiency of the two mesh sizes in taking 
carp of commercial sizes. 
NuMBER OF | NuMBER OF 
fig Siege Per CENT OF Comebaniee | CoMMERCIAL- 
Net Nate as ~~ - ~|TotraL NuMBER “ | Sizep Carp 
Net-Days ala : S1zED 
or Net-Days 2 _.| IN EXPECTED 
Carp Caucut | C 
ATCH 
Utnmhssneh os, oe cecal 508.12 16 413 | 461.32 
DeCh= Mesh Se vox. ohruk sn esse ee 156.10 24 194 145.68 
Wiha. PRR Nee a oy tisk het Oe 664.22 100 607 | 607 .00 
The following equation is based on the chi-square (x?) formula on page 337. 
= 5.06 + 16.03 = 21.09 
» _ (413 — 461.32)? i (194 — 145.68)? 
ee 461.32 145.68 
_ Fig. 10.—Trap net. This net is used by some fishermen who operate on the Mississippi 
River. Photo courtesy of Dr. John Moyle, Division of Game and Fish, Minnesota Department of 
Conservation, St. Paul. 
