July, 1955 
&9 to 11% inelie=; 
r to.al ‘engths was 108 
uiches. lhe two crappies taken in the sec- 
tion having an inner net of 3-inch mesh 
were each more than 11 inches in total 
length. The mean of the total lengths of 
white crappies taken at the various sta- 
tions in the 2 years of test-netting with 
various commercial devices was between 
7.5 and 8.0 inches, and of black crappies 
between 7.1 and 8.4 inches. As was the 
case with the bluegills, most of the crap- 
pies were too small to be taken in the 
trammel nets having meshes of 11% inches 
or larger. How much the crappie popu- 
lation of the Caruthersville-Dubuque sec- 
tion of the Mississippi fluctuates from 
year to year in abundance of individuals 
of different size or age groups is not 
known; however, the differences in indi- 
vidual lengths between the 1944 and the 
1946 samples from the river were not 
great (Barnickol & Starrett 1951:317). 
It was shown by test-netting that, al- 
though trammel nets will catch sport 
fishes, if a mesh of 2 inches or larger size 
is used, the catch of these fishes is nom- 
inal, even when the nets are fished in 
waters having a high population of crap- 
pies and such other common sport fishes 
as are found in the Caruthersville-Du- 
buque section of the Mississippi River. 
Gilling Experiment With Set 
Trammel Net.—Some critics of the 
trammel net have claimed that the net 
not only captures large numbers of sport 
fishes, but that sport fishes are killed in 
the net by gilling. Gilling occurs when a 
fish strikes the inner fine-mesh net and 
forces its head through the netting far 
enough to allow the net twine to become 
lodged beneath one or both gill covers. 
The gills may be injured while the fish 
is trying to escape or while a fisherman Is 
dislodging the fish from the netting. Re- 
lease of a gilled fish requires of the fish- 
erman more time and patience than does 
release of a pocketed fish. Pocketed fish 
are seldom injured in the net. 
In the trammel net experiment at Graf- 
ton in October, 1944, a record was kept 
of the section of the net in which each 
fish was caught, as well as whether the 
fish was pocketed or gilled in the net. 
The number and per cent of fishes that 
were gil'ed are listed by species and size 
STARRETT & BARNICKOL: COMMERCIAL FISHING DEVICES 361 
Seana! 
analy 
‘n which the fish were caught, 
asle 245. Gilling was relatively greater 
among the buftalofishes than among any 
of the other commercial species. The high 
percentage of gilled buffalofishes might 
be due to the terrific force with which 
these fishes hit a trammel net. A fisher- 
man trying to hold buffalofishes alive for 
a period of time in a crib or holding pond 
might experience a higher mortality 
among the gilled fish than among the 
pocketed fish. 
Persons who have fished gill nets know 
that the sunfishes, including the crappies, 
the bluegill, and the basses (Micropterus 
spp.), are ordinarily a difficult group to 
take in large numbers in these nets, 
whereas the perches and similarly shaped 
fish are taken readily in them. A low per- 
centage of gilling was recorded for the 
crappies in the section of the trammel net 
having a 114-inch-mesh inner net, table 
28. Of 61 crappies taken in this net, only 
8 were gilled. These gilled fish ranged in 
total length from 8.2 to 10.2 inches, and 
the mean of their total lengths was 8.8 
inches. The crappies that were pocketed 
ranged in length from 7.4 to 12.2 inches, 
and the mean of their total lengths was 
9.4 inches. Although the mean of the 
total lengths for the pocketed crappies was 
higher than that for gilled fish, some of 
the pocketed fish were smaller than any 
of the gilled fish. 
The percentage of gilled crappies in the 
section of the experimental net with the 
2-inch mesh was higher than in the section 
with the 114-inch mesh; however, there 
were twice as many gilled crappies in the 
section with the 11-inch mesh as in the 
section with the 2-inch mesh. No sport 
fish was gilled in that section of the net 
with the 3-inch mesh. 
Catches With Floated Trammel 
Net.—Current and a clean river bottom 
are requirements for fishing with a train- 
mel net that is to be floated or drifted. 
The floats on the net must be of such 
buoyancy and the weights of such weight 
as to hold the narrow axis of the net in a 
nearly vertical position. The fisherman 
lays his net in an area of the channel he 
desires to fish and lets the current carry 
the net downstream over a clean sand or 
gravel bottom. 
In the D-MR section of the Mississippi 
