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Pahrump poolfish: Are they too naïve to live?

By Nicholas Gerbis
Published: Monday, October 3, 2022 - 4:25pm
Updated: Monday, October 3, 2022 - 5:54pm
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USFWS/USFWS
The Pahrump poolfish

For 10,000 years after a thawing ice age dried up their lakes, three species of poolfish survived in small, isolated springs in the Mojave Desert’s Pahrump Valley, located an hour west of Las Vegas.

Only one species remains, and it might be too naïve to survive, according to research published in the Proceedings of the Royal Society B.

“Predator naiveté” means an animal lacks the ability to sense and avoid predators.

It is perhaps most common in fish that evolve in isolation.

Normally, fish can sense danger by detecting the preyed-upon remains of one of their own in the water. This knack tells them when to flee and can teach them to recognize new threats.

But when researchers chummed the waters of a fish tank with Pahrump poolfish pieces, the fish did not react.

This fact adds credence to the hypothesis that invasive predators caused population crashes when the endangered fish were transplanted to new habitats.

On the bright side, Pahrump poolfish populations have recovered well when not threatened by non-native predators, so the authors recommend managers keep them in single-species refuge habitats.

Science Sustainability