Naked sand darter


The naked sand darter is a freshwater fish of the family Percidae. It is found in the south-eastern United States.

Description

The naked sand darter is a small fish ranging in size from 40 to 50 mm long, the maximum being around 64 mm. Being a long thin darter, it is devoid of scales with the exception of a few rows above and below the lateral line and sometimes the caudal peduncle. Slightly transparent in life with a yellow color and iridescent operculum, the naked sand darter blends in with its habitat. It has darker bands in the dorsal, anal, and caudal fins with a whitish base and tip. Males of breeding size with have a dark spot at the front of the dorsal fin. Unlike similar darters, it does not have an opercular spine.

Diet

Larvae of small fish are the primary source of food for naked sand darters. They also feed on smaller crustaceans like copepods or clam larvae depending on their size. Naked sand darters feed continuously throughout the day, but stop at night. They also feed less in winter and summer months then pick back up before and after breeding season.

Habitat

Naked sand darters prefer the sandy bottoms of clean, freshwater rivers and streams. They can be found about 1 m deep on the bottom, digging into the sand to wait for prey to swim by.

Distribution

They can be found exclusively along the Gulf of Mexico in the rivers and drainages of eastern Louisiana to as far east as the Mobile Bay drainage in Alabama. Naked sand darters have been found as far north as West Tennessee.

Reproduction and lifecycle

Breeding season is from March or April until September or October when water temperatures are between 17 and 29 °C. Males develop tubercles on their anal and pelvic fins to aid in fighting for females. Females can produce from 12–122 eggs at a time and reach sexual maturity after a year. They only live 24 to 30 months.

Etymology

The genus name, Ammocrypta, comes from the Greek word ammos meaning sand and the Greek kryptos meaning hidden. The species name, beanii, comes from the first collector of the species, Tarlton H. Bean.