How to Identify Tule Perch

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

Physical Characteristics

Body shape

compressed

Coloration

Highly variable, ranging from silvery to olive-green or brownish on the back, fading to silvery or whitish on the belly. Often with irregular dark blotches or vertical bars on the sides. Fins are typically dusky or clear. Breeding males can develop more intense coloration.

Scale type

ctenoid

Mouth position

terminal

Distinctive features

Deep, compressed body, Relatively small mouth, Long dorsal fin with both spiny and soft rays, Viviparous reproduction (live-bearing), Only freshwater species in the surfperch family (Embiotocidae)

Dorsal fin

Single, long dorsal fin with 9-11 strong spines anteriorly and 14-17 soft rays posteriorly, often with a notch between the spiny and soft portions.

Tail fin

Moderately forked caudal fin.

Pectoral fin

Pectoral fins are relatively small and rounded.

Distinctive fins

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

Identification Tips

1. 1

   Body Shape

   Look for a distinctly deep and compressed body, typical of surfperches, but in a freshwater environment.

2. 2

   Dorsal Fin

   Observe the single, long dorsal fin with a clear division between the spiny anterior portion and the soft-rayed posterior portion.

3. 3

   Coloration

   Note the variable coloration, often with dark blotches or bars, which can help distinguish it from other native freshwater species.

4. 4

   Viviparity

   If observed during breeding season, the presence of live young being born is a definitive characteristic.

5. 5

   Geographic Location

   Its presence in freshwater systems within California is a key identifier, as it's the only freshwater surfperch.

Explore Tule Perch