How to Identify Tule Perch

To identify Tule Perch (Hysterocarpus traskii), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Variable, typically olive-green to brownish on the back, fading to silvery on the sides and belly. Often exhibits 6-9 dark vertical bars or blotches along the sides, which can be more prominent in some individuals or during certain behaviors. Fins are generally dusky.

Scale type

cycloid

Mouth position

terminal

Distinctive features

Deep, compressed body, Relatively large, cycloid scales, Single, long dorsal fin with both spiny and soft rays, Viviparous (live-bearing) reproduction, Only freshwater species in the family Embiotocidae

Dorsal fin

Single, long dorsal fin with 9-11 spines followed by 19-23 soft rays. The spiny and soft ray portions are continuous.

Tail fin

Slightly forked or emarginate caudal fin.

Pectoral fin

Moderately sized, rounded pectoral fins.

Distinctive fins

Anal fin with 3 spines and 19-24 soft rays. Pelvic fins thoracic, with 1 spine and 5 soft rays.

Identification Tips

1. 1

   Body Shape

   Look for a distinctly deep and compressed body, similar to a sunfish or crappie, but with a more elongated dorsal fin.

2. 2

   Coloration and Markings

   Observe the olive-brown to silvery body with 6-9 dark vertical bars or blotches on the sides. These bars can be faint or prominent.

3. 3

   Dorsal Fin

   Note the single, continuous dorsal fin that extends for a significant portion of the back, comprising both spiny and soft-rayed sections.

4. 4

   Scales

   The scales are relatively large and cycloid (smooth-edged), giving the fish a somewhat smooth appearance.

5. 5

   Viviparity (Live-bearing)

   While not an external identification feature, the knowledge that this is the only live-bearing freshwater fish in North America is a key biological identifier.

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