360 Ittinois NATURAL History SuRVEY BULLETIN 
The catch of commercial species in the 
27 experimental sets was low, since no 
effort was made to search out such spe- 
cies. 
In the 27 sets, 247 fish were caught, 
table 28. The section with the 11-inch- 
mesh inner net caught 165 fish, or 66.8 
per cent of the number of fish taken; the 
section with the 2-inch-mesh inner net 
took 71 fish, or 28.7 per cent of the total; 
and the section with the 3-inch-mesh in- 
ner net took only 11 fish, or 4.5 per cent 
of the total. 
Of the 165 fish taken in the section 
with the 114-inch-mesh inner net, 44.8 
per cent were sport fishes, 35.8 per cent 
were garfishes and bowfins, and 13.9 per 
cent were commercial species. Crappies 
comprised 82.4 per cent of the number of 
sport fishes taken in the section with the 
114-inch-mesh inner net. Of the remain- 
ing 17.6 per cent of the sport fishes, six 
were bass (Micropterus spp.), four were 
bluegills, two were yellow bass, and one 
was a warmouth. Bullheads were the 
principal commercial fishes taken in the 
section with the 114-inch-mesh inner net. 
Seven buffalofishes, one carp, and three 
carpsuckers formed the remainder of the 
commercial catch. 
Commercial species, principally buffalo- 
fishes and carp, made up 45.1 per cent of 
the number of fish caught in the section 
of the experimental trammel net with 2- 
inch-mesh inner net. In this section of 
the net, sport fishes comprised 28.2 per 
cent of the catch; crappies comprised 95.0 
per cent of the number of sport fishes. 
The section with the 114-inch-mesh inner 
net caught 3.7 times as many sport fishes 
as did the section with the 2-inch-mesh in- 
ner net. Only 2 garfishes were taken in 
the section with the 2-inch-mesh inner 
net and 48 in the section with the 114- 
inch-mesh inner net. 
Of the 11 fish caught in the section 
with the 3-inch-mesh inner net, 72.7 per 
cent were commercial species. This sec- 
tion of the net caught but 2 sport fishes. 
Of the three mesh sizes used in the ex- 
perimental trammel net, the 2-inch size 
appeared to be by far the best for com- 
mercial fishing. The section of the net 
having an inner net of this mesh size had 
the highest catch of commercial species, 
it had few garfishes, and it had a catch of 
Vol. 26, Art. 4 
sport fishes that was low when it is con- 
sidered that the net was fished in waters 
known to contain a high population of 
these fishes, table 28. If sport fishes of 
larger sizes had been abundant in the 
waters fished, perhaps the catch of these 
fishes would have been much higher in 
this section of the net. The section with 
the 3-inch-mesh inner net would probably 
have taken a high catch of large commer- 
cial species if fished in a habitat being 
used by such fishes. This section of the 
net took very few sport fishes of the sizes 
then present in the Grafton waters. 
In conjunction with the trammel net- 
ting experiment at Grafton, 12 net-days 
of fishing were done with 1-inch-mesh 
wing nets. Ninety-one bluegills were 
taken in these wing nets; they ranged in 
size from 3.8 to 7.6 inches total length. 
The mean of the total lengths of these 
bluegills was 5.7 inches. The four blue- 
gills taken in that section of the experi- 
mental trammel net having a 11%-inch- 
mesh inner net ranged from 7.0 to 7.2 
inches in length. Evidently most of the 
bluegills present in the Grafton waters in 
the fall of 1944 were too small to be 
taken in the 114-inch-mesh net. If blue- 
gills of 7 inches and longer had been ex- 
tremely abundant, the catch in the ex- 
perimental trammel net probably would 
have been higher. The mean of the total 
lengths of bluegills taken in the Missis- 
sippi River during the 2-year survey with 
all types of fishing devices was between 
6.1 and 6.5 inches. In the 116 trammel 
net sets made during the survey, only 20 
bluegills were caught, table 26. On the 
basis of the above discussion, it appears 
that trammel nets having inner nets with 
meshes of 114 inches or larger are quite 
inefficient in taking bluegills in the Ca- 
ruthersville-Dubuque section of the Mis- 
sissippl. 
In the 12 net-days of fishing with wing 
nets at Grafton, 285 crappies were taken. 
These fish ranged in total length from 
4.4 to 11.4 inches; the mean of their total 
lengths was 7.6 inches. Crappies caught 
in the section of the experimental net hav- 
ing an inner net of 114-inch mesh ranged 
in total length from 7.4 to 12.2 inches; 
the mean of their total lengths was 9.3 
inches. Crappies taken in the section hav- — 
ing an inner net of 2-inch mesh ranged 
