TN00073 SHARPHEAD DARTER ETHEOSTOMA ACUTICEPS
Physical description: This is a barred, sharp-snouted darter of moderate size. The adults are usually from 35-60 mm SL. The body form is moderate in profile and compressed with the snout the narrowest and sharpest in the subgenus. The frenum is well developed, and the branchiostegal are seperate to narrowly conjoined. The caudal fin is subtruncate to slightly rounded. The females genital papillia is small and flattened or bulbous. The lateral line is complete with 0-9 unpored scales and 54-65 scales to the caudal base. There are (3)4-6(7) scales above the lateral line and 8-9 scales below the lateral line. There are 22-27 circumpeduncle scales, 11-13 dorsal spines and 11-13 dorsal rays. There are 1-2 anal spines, 7-9 anal rays and 12-14 pectoral rays. The nape, cheek, opercle and breast are naked and the belly is fully scaled. The nuptial male has a dark olivew dorsum, a tan venter and a side that occationally has a turquoise tinge. The cheek and opercle are olive-brown and the branchiostegals are a suffuse pale orange. The breast is blue-greeen. The first dorsal fin has suffuse turquoise diatally and the remainder is dark olive. The other fins are brighter turquoise, with the anal the most so, and the pectoral usually the least. The nuptial female and the nonbreeding males have a straw-olive to brown-olive head and body with a yellow venter. The fin rays are olive-yellow to straw-yellow *4205*. Reproduction: The development of sharphead darter eggs begins during April. Ovarian weights peak in late June, then decrease during July and August as the mature eggs are deposited. E. acuticeps were collected in breeding condition from late June until the 15th of August making it one of the latest (possibly the latest) spawning darters (the spawning period probably does not begin until June). Mature ova average about 1 mm in diameter. Sexual maturity is reached at one year, although some authors contest that spawning begins once individuals reach 2-3 years of age. The number of eggs produced increases with the length of the female, and a large female (55 mm) produced nearly 300 eggs, whereas a fish of 39 mm produced only about 100 eggs. The female buries eggs in sand in riffle areas. Individuals live a maximum of less than 3 years *809,796,791,2208,785*. Aggressive tail biting has been noted during the breeding season. In the Holston River, Virginia, they breed from late-June to mid August. Spawning occurs in swift areas but has been unwitnessed *4205*. Behavior: This species is very aggressive during the breeding season, when males line up head to tail about 3 cm apart. They change colors, and erect all of their fins. The vertical bars on the sides of the fish darken, with the darkness extending through the eyes, giving the appearance of a mask. After several seconds, the fish lunge at the caudal fin of other fish in an attempt to bite it *785*. They feed on mayfly, midge, and blackfly larvae. They also take caddisfly and other larvae *4205*. Origin: This species is endemic to the upper Tennessee drainage of the Ohio Basin *796,791,4205*. Limiting factors: The reasons for their disappearance from the few stream sections where it was once known may be cases cited herein of pollution, turbidity, siltation, impoundments, and cool to cold water discharges *809*. Population parameters: This species has a sex ratio of 1.5:1 (females to males) *2208*. Aquatic/terrestrial associations: The substrate of the riffle area is cobble and small boulder, usually well covered with riverweed (Podostemum cerato- phyllum). Riffles are typically shaded by large trees and bordered by beds of waterwillow (Justicia americana) *786*. They are often associated with E. blennoides and E. zonale (during certain times of the year these species are rare, apparently moving into deeper water to spawn) *785*. PHYSICAL DESCRIPTION: MEDIUM SIZED DEEP BODY DARTER, MAXIMUM LENGTH ABOUT 3 INCHES, 8-9 DORSAL SADDLES, LATERAL LINE COMPLETE WITH 54-62 SCALES, DORSAL FIN WITH 11-13 SPINES AND 12-13 RAYS REPRODUCTION: SPAWNING FROM MID-JUNE THROUGH MID-AUGUST, FECUNDITY AVERAGES UP TO 300 OVAFEMALE, LIFE SPAN IS ABOUT 3 YEARS
| Life History |
References for Life History Codes
9286, 809, 786, 780, 796, 791, 2208, 777, 785, 4205
Comments on Life History Codes
E. acuticeps appears to be the least colored of the 13 species of Nothonotus (subgenus of Etheostoma), a group noted for its elegantly colored members *809*. E. acuticeps is the only species of Nothonotus with an unscaled opercle and no red pigment *2208*. The gill membranes of E. acuticeps are narrowly, but distinctly conjoined, unlike the condition in other species of Nothonotus, in which they are separate *777*. The standard length is that length of a given fish from the tip of its snout up to, but not including, the caudal fin *2208*.