72 James C. Widlak and Richard J. Neves 



habits. If fewer than 10 fish were collected in a month, all specimens 

 were examined. Stomach contents were removed, sorted, identified to 

 order or family (Hilsenhoff 1975; Merritt and Cummins 1978; Barnes 

 1980), and counted. Sampling to determine feeding chronology was 

 conducted on 2 July, 13 August, and 9 September 1981. Twelve to 

 twenty-four darters were collected during each of six 4-hour intervals 

 (1200, 1600, 2000, 2400, 0400, and 0800). Stomach contents were pooled 

 for each sampling time, blotted on a paper towel, and volumetric dis- 

 placement was measured with a 1 cc plastic syringe. Mean stomach 

 volume for each time interval was computed. These 24-hour samples 

 (329 fish) were also included in seasonal food habits analyses. 



Reproduction 



The reproductive cycle of the male was studied by recording the 

 size and appearance of testes of 427 males, and by external body colora- 

 tion. Ovaries and digestive tracts of females were removed, and the 

 ovaries weighed to the nearest 0.01 g. Adjusted body weights (body 

 weight after removal of stomach, ovaries, intestinal tract, and liver) of 

 females were also obtained. Ovaries were examined under a dissecting 

 microscope and classified as (1) gravid - containing maturing eggs; (2) 

 ripe - containing ripe eggs; (3) spent - containing some ripe eggs and 

 showing apparent resorption; and (4) resting - containing no mature or 

 maturing eggs. All eggs in both ovaries were counted and categorized 

 as (1) mature (ripe) - largest in size, translucent, indented, and contain- 

 ing a single large oil globule; (2) maturing - intermediate in size, opaque, 

 and yellow; and (3) immature - smallest in size, round, and white. Sam- 

 ples of 10 mature and maturing eggs from each pair of ovaries were 

 measured to the nearest 0. 1 mm with an ocular micrometer. A gonoso- 

 matic index (GSI) was calculated for females by multiplying the ovary 

 weight by 1000 and dividing by the adjusted body weight (Burr and 

 Page 1978, 1979); values were then plotted over time. No female darters 

 were collected in January and only two in December; consequently, 

 these months were not represented in the GSI computations. Analysis of 

 covariance tested for homogeneity between ovary weight and body 

 weight, total length, login body weight, and cube of total length (de 

 Vlaming et al. 1982). Relations between ova diameter, number of 

 mature and maturing ova, and total length of female, and ova number 

 and adjusted body weight in pre-spawning fish were computed by sim- 

 ple linear regressions. Attempts to observe spawning at the study site 

 and in the laboratory, and to rear darters for larval descriptions, were 

 unsuccessful. 



RESULTS AND DISCUSSION 



The redline darter was the predominant darter and one of the most 

 abundant fish species at the study site. A total of 682 was collected 



