How to Identify Rio Grande Cutthroat Trout

To identify Rio Grande Cutthroat Trout (Oncorhynchus clarkii virginalis), look at these key features.

Physical Characteristics

Body shape

torpedo

Coloration

Overall body color ranges from golden-bronze to yellowish-green, often with a reddish or orange tint along the lateral line and belly. The back is typically darker, olive to brown. Spots are sparse, relatively large, and irregularly shaped, concentrated mostly on the posterior half of the body, caudal fin, and dorsal fin. The characteristic red or orange 'cutthroat' marks are present in the gular fold beneath the lower jaw.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Red or orange 'cutthroat' marks on the underside of the lower jaw., Sparse, large, and irregularly shaped spots concentrated towards the tail., Often a golden-bronze or yellowish-green body coloration., Presence of basibranchial teeth (a small patch of teeth on the floor of the mouth).

Dorsal fin

Single dorsal fin, typically with 8-12 rays, often spotted.

Tail fin

Slightly forked caudal fin, often heavily spotted.

Pectoral fin

Paired pectoral fins, typically clear or lightly spotted.

Distinctive fins

Adipose fin present, characteristic of salmonids.

Identification Tips

1. 1

   Cutthroat Marks

   Look for the distinctive red, orange, or sometimes yellow-orange slash marks in the folds under the lower jaw. This is the most reliable identifying feature for all cutthroat trout subspecies.

2. 2

   Spotting Pattern

   Rio Grande Cutthroat Trout typically have sparse, relatively large, and irregularly shaped spots that are more concentrated on the posterior half of the body, especially towards the caudal fin. This contrasts with the finer, more numerous, and evenly distributed spots of many other trout species.

3. 3

   Body Coloration

   Observe the overall body color, which often has a golden-bronze or yellowish-green hue, sometimes with reddish tints along the lateral line. This can vary depending on habitat and diet.

4. 4

   Basibranchial Teeth

   While requiring careful examination, the presence of a small patch of teeth on the floor of the mouth (basibranchial teeth) is a characteristic of cutthroat trout and can help distinguish them from rainbow trout.

Explore Rio Grande Cutthroat Trout