Darters and Walleye

Darters and Walleyes
Family: Percidae
Genus: Etheostoma, Sander
These fish tend to be found in clear fast moving streams and rivers. Occasionally they can be found in Amistad itself. Many of them host vibrant colors and displays that set them apart from most anything else.

1. Separated dorsal fins
2. Usually ornately colored
3. Lateral line usually visible and starts from eye-level or higher, does not extend visibly beyond the anal fin.

 

Greenthroat Darter

Chad Thomas

Greenthroat Darter
(Etheostoma lepidum)
While currently considered stable, the greenthroat may be in danger of becoming threatened due to loss of habitat. They usually reside in the springs of the edwards plateau and riffle streams. Due to water supply issues, these and many darters are on the precipice of endangerment.
Colors can vary greatly on most darters. The green throat can be differentiated from the rio grande darter by the mottling pattern as opposed to dots and lines. It also has a completely scaleless opercle.

 

Rio Grande Darter

Chad Thomas

Rio Grande Darter
(Etheostoma grahami)
This darter is considered state threatened, primarily due to habitat loss. It is commonly found in riffles and springs, specifically in the devils river and the San Felipe Springs. They tend to favor fast moving water with gravel and rubble substrate. Recent studies suggest that across a number of systems they are rare, they are nonetheless persistent and surviving. Studies have shown that the same efforts being made to protect the Devils River minnow may benefit this darter.
The Rio Grande darter body has small red dots that may or may not form lines, and females can have black spots. This darter has a heavily scaled opercle

 

Walleye

Chad Thomas

Walleye
(Sander vitreus)
Walleye traditionally prefer shaded rivers, and streams. While they are often stocked into reservoirs, the do not usually flourish. They are associated with the extinction or suppression of darters and minnows. The juvenile walleye will occupy the same habitat as these fish and can wipe them out through predation.
Significantly larger than darters, and possesses a forked caudal fin. The lateral line is complete and usually visible all the way to the caudal fin. Juvenile walleyes can be differentiated from darters by the sharp and serrated opercle and the receded upper jaw.