Fish of Pinnacles National Park

Intermittent Streams and Fish

Native Species

Due to the intermittent nature of Pinnacles’ streams, the three-spined stickleback is the only native fish species in the park. This predatory fish primarily feeds on aquatic insects and can grow up to three inches long when fully mature. The stickleback is often observed along the Bear Gulch and South Wilderness Trails. Occasionally, other fish species may swim upstream from the Salinas River during floods, but they typically do not survive through the summer's dry conditions.

Non-Native Species

• Catfish: In the early 1980s, non-native catfish were present in the park’s reservoir. This population was eradicated in the mid-1980s by draining the reservoir and electroshocking the remaining fish.
• Green Sunfish: In the mid-1990s, non-native green sunfish infiltrated park streams. They posed a significant threat to the red-legged frog population and were removed using electroshocking techniques.
• Mosquitofish: Currently, the mosquitofish is the only non-native fish species in the park. While its impact on red-legged frogs is minor, eradicating it is currently impractical.