70 James C. Widlak and Richard J. Neves 



Ohio River basin, but one species occurs in direct tributaries of the 

 lower Mississippi River, one in the Mobile Bay drainage, and two in the 

 Ozarks. Of the 13 species, life history studies have been conducted only 

 on Etheostoma acuticeps Bailey, the sharphead darter (Jenkins and 

 Burkhead 1975; Bryant 1979) and Etheostoma maculatum Kirtland, the 

 spotted darter (Raney and Lachner 1939), and comparative ecological 

 studies were done on 3 species (Stiles 1972). 



The redline darter occurs in tributaries of the Tennessee and Cum- 

 berland rivers in Virginia, North Carolina, Tennessee, Kentucky, Geor- 

 gia, Mississippi, and Alabama (Etnier 1980). It is found in swift, shallow 

 riffles of clear streams and may exist in riffles shallower than those pre- 

 ferred by other Nothonotus species (Zorach 1970). Except for studies on 

 systematics (Zorach 1970) and breeding and food habits of three 

 Nothonotus species (Stiles 1972; Bryant 1979), no biological informa- 

 tion is available on the redline darter. The present study was conducted 

 to describe age, growth, food habits, and spawning of a population in 

 Virginia. 



MATERIALS AND METHODS 



Study Area 



Field sampling was conducted on the North Fork Holston River, a 

 fourth-order stream in the Ridge and Valley Province of southwestern 

 Virginia. The study site was a 350 m section at River Mile 86.9 

 (36°55'N, 81°40'W), about 8 km upstream from Saltville, Smyth 

 County. The river at this site averages 29 m wide and consists primarily 

 of riffle habitat with cobble and boulder substrate. Water temperatures, 

 recorded daily with a Ryan 30-day thermograph, ranged from 1°C in 

 February to 29° C in July. Water quality characteristics, collected 

 monthly and analyzed with a Hach DR-EL/ 1 field kit, are summarized 

 in Table 1. Detailed water quality data for the North Fork Holston 

 River were compiled by Poppe (1982). A total of 41 fish species occurs 

 at the study site (Widlak 1982). 



Fish Collections 



Redline darters were collected twice monthly from May to August 

 1981, and monthly from September 1981 to May 1982. Sampling was 

 done exclusively with a Coffelt BP-1 backpack electroshocking unit 

 with direct current output, and dip nets. Waterscopes were used to facil- 

 itate sighting of darters during high water levels. All habitats were elec- 

 trofished to obtain representative samples of redline darters, and an 

 attempt was made to collect at least 10 darters on each sampling date. 

 Seventeen to one-hundred twenty-six specimens were collected per sam- 

 ple during summer and fall sampling, but only three to seventeen were 

 collected during the winter months because of high water levels or ice 

 conditions. Specimens were placed on ice to reduce regurgitation of 



