92: Plains Orangethroat Darter

Pretty small fish with a sex ratio of 7 males to 1 female

I write to you from Arapahoe, Ute, and Cheyenne land. I am interested in learning about the different animals that live in the place where I was born. Before we start with today’s animal, I want to emphasize that biological classification as understood by western society has its roots in racism, sexism, and transphobia – here’s a good explainer about why.

The Orangethroat Darter (Etheostoma spectabile) lives in northeastern Colorado, with the rest of its range to the east of our state. In Colorado, they live in streams, mainly in the Republican River Basin. Like many of the fish we talk about here, the glaciers of the Ice Age have an important role to play in their current lives. The streams they live in spring from the High Plains Aquifer, an underground body of water that is the remnant of melting glaciers from the end of the Pleistocene ca. 12000 years ago. The Aquifer is not replenished by rainfall. The Aquifer is also a major source of agricultural water and it has been pumped relentlessly in the 20th and 21st centuries. From a study in Ecohydrology:

“A research team from Oregon State University spent three years studying the Arikaree River in eastern Colorado, mapping refuge pools left during dry periods and the connectivity between these. The results were then compared with historical data on the area.

“Their conclusions were shocking. Even in the most optimistic circumstances in the next 35 years only 57% of the current refuge pools would still be in existence and almost all of these would be contained within an isolated mile long stretch of the river.

“This lack of year round habitat could have devastating consequences on the ability of native fish such as Brassy minnows (Hybognathus hankinsoni) and Orange-throat darters (Etheostoma spectabile) to survive dry periods by impeding their life cycles and limiting their ability to recolonise.”

Luckily they are abundant and unthreatened in other parts of their range where streams are made differently.

Orangethroat Darters are very pretty (beautiful photos here). They’re another of the “small fish” of Colorado.