July, 1955 
cient devices for catching channel cat- 
fish, table 5. However, these large-mesh 
nets were found to be the most efficient 
devices tested for taking commercial-sized 
STARRETT & BARNICKOL: COMMERCIAL FISHING DEVICES 
353 
nets did not take as many sport fishes per 
net-day as the 1l-inch-mesh wing nets, ta- 
bles 5 and 23; however, they took more 
than the nets of 214-inch-mesh. The trap 
Table 23.—Composition of catches of commercial-sized or cesirable-sized fish taken in 
114-inch-mesh trap nets (with leads) and in l-inch-mesh wing nets (without leads) in fisheries 
survey of the Mississippi River between Andalusia, Illinois, and Dubuque, Iowa, 1946. 
114-IncH-MeEsu Trap Ner 1-IncH-MeEsu Wine Ner 
(50.53 Net-Days) (200.50 Net-Days) C 
HI- 
Kinp oF FisuH SQUARE 
Pounds Number | Pounds Number VALUE 
per Number per per Number per 
Net-Day Net-Day | Net-Day Net-Day 
Mees oes ss 2.78 37 0.73 0.96 43 0.21 34.45* 
Bigmouth buffalo. .. = 0 — 0 —- = 
Smallmouth buffalo . = 0 — a 2 0.01 — 
Freshwater drum.... 0-29 14 0.28 0.26 56 0.28 0.00 
Channel catfish..... 0.05 2 0.04 0.04 5 0.02 0.32 
Flathead catfish..... — 0 — 0.15 9 0.05 
epalleg rise cic 3: ~~ 2 0.04 _ 21 0.10 1.84 
White crappie...... —— 20 0.40 — 131 0.65 431% 
Black crappie....... | — 6 0.12 — 1S 7, 0.68 22325 
| 
* Denotes a significant difference, in numbers of commercial-sized or desirable-sized fish taken, 
types of nets at 0.05 level with 1 degree of freedom. 
flathead catfish. Of the flatheads taken 
with these nets in 1946, 95.1 per cent 
were 18 inches or more in total length, 
table 20. In the 1-inch-mesh wing net 
collections of 1946, only 23.5 per cent 
were 18 inches or more in total length. 
The mean of the total lengths of flatheads 
taken in 1946 in the 214-inch-mesh hoop 
nets was 26.19 inches, table 20, as com- 
pared with 15.39 inches in the 1-inch 
mesh wing nets and 13.20 inches in the 
l-inch-mesh hoop nets, table 18. In the 
1946 test-netting, the mean of the total 
lengths for the 58 flatheads taken in the 
214-inch-mesh hoop nets was about the 
same as the mean for the + flatheads in 
the 214-inch-mesh wing net collections, 
table 22. 
The catch of sport fishes in the 214- 
inch-mesh hoop nets amounted to less 
than 0.01 fish per net-day in 1946, table 
5. In this same year, the catch of sport 
fishes was 5.43 fish per net-day in the 
l-inch-mesh wing net collections. 
Catches With Trap Nets.—Trap 
nets were fished at only three stations for 
a total of 50.53 net-days. The nets were 
all of 114-inch mesh. As indicated by 
fig. 12, the catch with these nets included 
both commercial and sport fishes. “These 
between the two 
net sets made during this investigation 
were too few in number to give any con- 
clusive evidence regarding usage of these 
nets on the Mississippi. 
Entanglement Device 
The trammel net is the only entangle- 
ment device that was used in the survey. 
This device is composed of three separate 
nets secured to a single top and a single 
bottom line. The two exterior nets (for 
purposes of explanation called here left- 
exterior and right-exterior) are made of 
heavy twine and have a mesh size of 8 to 
10 inches. The inner net is a small-mesh 
gill net loosely sandwiched between the 
two large-mesh outer nets, fig. 13. 
A fish swimming into a trammel net 
from the left side passes freely through the 
left-exterior net and strikes the loosely 
hung inner net with enough force to carry 
a portion of the inner net with it through 
a mesh opening of the right-exterior net. 
The inner net, passing through a mesh of 
the right-exterior net, forms a pocket in 
which the fish is enclosed. Similarly, a 
fish approaching the trammel net from the 
right side passes through the right-exte- 
rior net and becomes trapped in a pocket 
