16 
Fred C. Rohde and Steve W. Ross 
Table 4. Numbers of Etheostoma mariae by sex in each age class collected 
from Naked Creek, North Carolina, and aged by scale reading. 
Sex 
0 
Age Class 
1 
2 
Total 
Male 
60 
33 
6 
99 
Female 
114 
61 
29 
204 
Total 
183* 
94 
35 
312 
Percentage 
of total 
58.65 
30.13 
11.22 
* Nine of 312 fish aged were unsexed (immature). 
Table 5. Relative survival values by sex of Etheostoma mariae year classes. 
IX 1 : 
proportion of age class 0, 1 
x = proportion of age class 1. 
Year Class 
N 
1 x 1 
1 x 2 
Males 
0 
60 
1.000 
- 
1 
33 
0.550 
1.000 
2 
6 
0.100 
0.182 
Females 
0 
114 
1.000 
- 
1 
61 
0.535 
1.000 
2 
29 
0.254 
0.475 
Total 
0 
183* 
1.000 
- 
1 
94 
0.514 
1.000 
2 
35 
0.191 
0.372 
* Nine immature 
fish of the 312 aged 
were not sexed. 
in increasingly greater numbers as fish size increased. Hydropsychids 
were the second most important food of the largest darters (> 49 mm). 
Although not important overall, ostracods were most evident in the diet 
of young fish (< 30 mm). Such feeding on small crustaceans by young 
darters, followed by an increse in use of larger aquatic insects as the fish 
grows, is common among darters (e.g. Scalet 1972, Page 1983). 
The diet of E. mariae reflects its habitat. Young darters may 
inhabit quiet waters near shore and in deep pools, where they consume 
large numbers of ostracods that also prefer such areas (Pennak 1978). 
Adult darters were more common in the swift portions of the stream. 
They fed primarily on insects either attached to, crawling on (e.g. dip- 
terans, trichopterans, ephemeropterans), or beneath (e.g. plecopterans) 
the gravel/ rubble substrate. The proportion in which these insects are 
consumed is dependent upon a combination of preference, availability, 
and vulnerability of prey present. 
