348 
of 1-inch mesh than in the nets of larger 
mesh. The writers are unable to explain 
why the mean length for one species of 
crappie was greater in nets of l-inch mesh 
and the mean length for the other species 
was greater in the nets of larger mesh. 
In the nets of 1l-inch mesh, 24.0 per 
cent of the channel catfish and 29.5 per 
cent of the flathead catfish were of com- 
mercial sizes; in the nets of 11-inch 
mesh, 60.0 per cent of the channel catfish 
Ittino1is NaturAL History SurvEY BULLETIN 
Vol. 26, Art. 4 
and 50.6 per cent of the flathead catfish 
were of commercial sizes, table 13. The 
number of commercial-sized fish per net- 
day was greater for the channel catfish in 
the nets of l-inch mesh and for the flat- 
head catfish in the nets of 114-inch mesh, 
table 12. 
The 214-inch mesh was the largest 
mesh tested in wing nets. The 2 years of 
test fishing indicate that very few sport 
fishes are taken in nets of this mesh size, 
Table 15.—Composition of catches of commercial-sized or desirable-sized fish taken in 
2',-inch-mesh wing nets and in l-inch-mesh wing nets, both types without leads, in fisheries 
survey of the Mississippi River between Burlington and Dubuque, Iowa, 1946. 
214-Incu-MeEsuH Winco NEtTs 1-Incu-Mesu Winco Nets 
(421.75 Netr-Days) (855.86 Net-Days) ae 
HI- 
Kinp oF FisH SQUARE 
Pounds Number | Pounds Number VALUE 
per Number per per Number per 
Net-Day Net-Day | Net-Day Net-Day 
Rey os pees aan as 1.76 172 0.41 1.10 238 0.28 14. 86* 
Bigmouth buffalo. . . 0.31 44 0.10 0.04 13 0.02 50.35* 
Smallmouth buffalo.| 0.21 35 0.08 0.04 16 0.02 29 .28* 
Freshwater drum.... 0.22 47 0.11 0.23 210 0.25 25. on 
Channel catfish. .... 0.01 1 0.002 0.10 53 0.06 23.70* 
Flathead catfish. ... . 0.11 4 0.009 0.27 42 0.05 12.29% 
Pilea ei 3 aves as asst — 0 — — 97 0.11 —_ 
White crappie...... _ 6 0.01 — 1,228 1.43 590.01* 
Black crappie....... — 2 0.005 — 560 0.65 270.87* 
* Denotes a significant difference, in numbers of commercial-sized or desirable-sized fish caught, between the two 
types of nets at 0.05 level with 1 degree of freedom. 
Table 16.—Size ranges and means of the total lengths of fish taken in 2!4-inch-mesh wing 
nets and in l-inch-mesh wing nets, both types without leads, in fisheries survey of the Missis- 
sippi River between Burlington and Dubuque, Iowa, 1946. 
214-Incu-Mesu Winc Nets 1-Incu-Mesu Wine NEts 
' & | oa | n ' % = n 
ee lg |ad ee le |ad 
1S: ee ee ees SA ja | oe] ¢ é 
KinD oF FisH De ae BS Bp S  eeeeties aie So als 
eoRsgiog| 3 lJESiBlSiseelsa| &. (eel 
OsseS «S| Mg | Se OSH e8| oS] es Se) ee 
sgelGel be | gS |Selyee|Sol ge] ge (eee 
Reaiz<ciS4| eS |walesizd|S4| eS walac| + 
Car OAR ats Wenge 100.0 172) 20.28/15.4-31.8] 2.83) 78.5) 303) 17.55) 4.7-30.0/4.85] 227] 7.747* 
Bigmouth buf- 
RM ae ic 97.8 45) 17.14/13.8-20.1} 1.52) 39.4) 33) 13.48] 4.5-19.613.67| 38] 5.399* 
Smallmouth / 
beftalo.s.0:4.: 68.6 51) 15.74/12.4-26.0} 2.30) 5.8) 277) 9.21) 4.1-18.4)3.46| 118]17.036* 
Freshwater drum} 100.0 47 15.40/11.4-18.8] 1.41} 33.2) 632) 8.79] 4.0-18.6/2.93] 171/27.961* 
Channel catfish. .| 50.0) 2) 14.25) 5.7-23.0)12.37; 5.7) 936) 9.44) 2.7-30.1/2.21] 42) 0.550 
Flathead catfish.| 100.0; 4) 28.75/18.8-37.0] 7.15] 23.5] 179) 15.39) 5.6-37.65.30) 26) 3.714 
Bluegill......... — | OF — _ — 34.4, 282) 5.99) 3.0- 8.41.33} — = 
White crappie...| 100.0 6 10.42) 8.6-13.0] 1.85) 48.8/2,514) 7.36) 2.9-13.2/2.30| 122) 4.045* 
Black crappie...| 100.0, 2 10.50) 9.1-12.2] 2.21 41.71,343) 7.03) 3.0-14.0/2.14} 51) 2.220* 
| 
* Denotes a significant difference, in sizes of fish taken, between the two types of nets at 0.05 level for degrees 
of freedom indicated. 
