Etheostoma barbouri
Teardrop darter

Teardrop darters are an endemic species of the middle and upper portions of the Green River system in Kentucky and Tennessee from 38ºN to 36ºN (Kuehne and Small, 1971). (Kuehne and Small, 1971)

Teardrop darters are found in the freshwater aquatic drainage of the Green River in the temperate region of Kentucky and Tennessee. They are located in small to medium upland streams that are 2nd, 3rd, and 4th order tributaries. Adults are mostly collected in areas less than 0.66 meters deep and sometimes in pools of up to 1 meter deep and rarely seen in riffles (Kuehne and Small, 1971). Fry on the other hand have been found to occupy slow riffles and just below them (Flynn and Hoyt, 1971). They are flat rock bottom dwellers in low density of vegetative cover along sandy banks. Adults inhabit water with temperatures ranging from 21 to 27 degrees Celsius, whereas, eggs and larvae are found in water temperatures below 15 degrees Celsius (Tennessee Animal Biogeographic System Tabs, 2002). ("Tennessee Animal Biogeographic System Tabs", 12/2002; Flynn and Hoyt, 1979; Kuehne and Small, 1971)

Teardrop darters are divided into three age classes with a standard length of about 3 cm, 4 cm, and 4.5 cm. They are considered fully mature at 4.5 cm and weighing about 2.7 grams. They are bar checked darters and can be distinguished from the others by a darker sub orbital pigment bar, nine preoperculomandibular pores and less infraorbital and lateral line pores (Flynn and Hoyt, 1979). The Tennessee Animal Biogeography System website describes them as a slender fish having an incomplete lateral line with a count of 41 to 46 scales, 8 to 9 dorsal spines with dorsal ray counts of 12 to 14, and 2 anal spines with 8 to 9 anal rays. Teardrop darters are yellow with hints of orange, a dark head with a black bar by the eye, and black blotches on the body. They have dots on the caudal, anal, and second dorsal fins but the first dorsal fin is stripped and the pelvic fin is white to match the breast and belly. ("Tennessee Animal Biogeographic System Tabs", 12/2002; Flynn and Hoyt, 1979)

Eggs develop in 15 to 22 days depending on temperature. Fry can be found starting in late May with a standard length of 15 mm. Age can be determined by their scale annuli. Teardrop darters are divided into three age groups. After one year they reach a standard length of 31.9 mm and grow to 47.1 mm after reaching two years of age. (Flynn and Hoyt, 1979)

In teardrop darters, the sexes do not differ in appearance although males show a darkening through spawning season and after. Flynn and Hoyt (1979) also observed that there were no breeding tubercles, but females did have some inflammation in the genital papillae during spawning. (Flynn and Hoyt, 1979)

Males clear out areas underneath the rock with just enough room for the fish to fit with a fanning of their tail. One the nest site is ready, males will chase females into the site by bumping them. Both males and females invert their body during spawning. (Flynn and Hoyt, 1979)

Spawning season is April through May depending on the time it takes for the gonads to develop (Flynn and Hoyt, 1979). Each female lays 17 to 48 eggs (Flynn and Hoyt, 1979) underneath a flat stone monolayer with several using the same nest site (Page et al. 1982), and as many as 70 in one spot. Sexual maturity is complete at the end of the first year. Kuehne and Small (1971) describe reproduction as having a high resilience because the population can double in under fifteen months. Males have a yellowish growth on the dorsal fin in breeding season resembling an egg thought to compel females to lay eggs because females tend to select spots where others have deposited eggs earlier. (Etnier and Starnes, 2001; Flynn and Hoyt, 1979; Page and Burr, 1982; Etnier and Starnes, 2001; Flynn and Hoyt, 1979; Page and Burr, 1982)

Males have been observed guarding nests (Etnier and Starnes, 2001). It is not clear whether males are protecting young or just waiting for another mating opportunity since females prefer to lay eggs in established sites. Males have been observed eating fry. (Etnier and Starnes, 2001)

The age of teardrop darters can be detected by size or annulus formation. The maximum life span reported is two and a half years (Etnier and Starnes, 2001). Females rarely live to two years of age (Flynn and Hoyt, 1979). (Etnier and Starnes, 2001; Flynn and Hoyt, 1979)

Males will defend their territory from other competing males, chasing them off.

There is no information available on home range in this species.

Darters can produce a chemical, fright substance in the water to deter predators. (Etnier and Starnes, 2001)

Teardrop darters use their vision, tactile senses, and chemoreception to perceive their environment. (Etnier and Starnes, 2001)

Teardrop darters are carnivores. Their diet throughout life includes many different aquatic macroinvertebrates and occasionally detritus. Some of the most important food items for teardrop darters are the larval and adult stages of Diptera, Ephemeroptera larva, and Copepoda adults. (Flynn and Hoyt, 1979)

Besides being eaten by other teardrop darters, some predators include grass pickerel (Esox americanus americanus), banded sculpin (Cottus carolinae), water snakes (Nerodia), snapping turtles (Chelydra serpentina), belted kingfishers (Megaceryle alcyon), and little green herons (Egretta caerulea). (Flynn and Hoyt, 1979)

Teardrop darters hide and rely on their agility to deter predators. (Flynn and Hoyt, 1979)

The carnivorous diet, small body size, and short life span are the major factors in the teardrop darters' ecosystem roles. They are found to share the same area with the spottail darters (Etheostoma squamiceps). (Flynn and Hoyt, 1979)

Teardrop darters contribute to the diversity and enhance the beauty of the Green River basin. Teardrop darters could potentially have a greater importance to humans not currently understood.

Teardrop darters have no negative impact on humans.

Tennessee Wildlife Resources Agency (2002) has teardrop darters listed in non-game species in need of management. They are otherwise not listed as threatened or endangered. (Myers, 2002)

Etheostoma virgatum and Etheostoma obeyense are the closest relatives of teardrop darters. They seem to be allopatric species. (Kuehne and Small, 1971)

The teardrop darter was named after Professor Roger W. Barbour from the University of Kentucky. (Kuehne and Small, 1971)