Developing novel non-invasive environmental RNA (eRNA) tools for conservation of two endangered Bay-Delta fish species

PROJECT HIGHLIGHT

This project will develop novel non-invasive genomic tools to monitor two endangered fish species in the Sacramento-San Joaquin Delta by detecting RNA molecules they naturally release into the water. Unlike traditional monitoring that requires catching fish, this innovative approach using environmental RNA could provide more precise information about where these rare fish are and how they're doing.

PROJECT SUMMARY:

As environmental managers work to protect endangered species in the Sacramento-San Joaquin Delta, they need effective ways to monitor these species without disturbing them. While traditional monitoring involves physically catching and counting fish, scientists can now detect traces of DNA that organisms naturally shed into the water. Even more promising is the detection of environmental RNA (eRNA), a molecule that degrades more quickly than DNA and is only produced by living organisms. Because eRNA breaks down so rapidly, finding it in water samples provides very recent evidence of where organisms are and how they're doing. The presence and amount of eRNA can even reveal if animals are stressed by environmental conditions like high temperatures.

This project aims to develop new tools using eRNA to monitor two endangered California fish species — delta smelt and longfin smelt — without having to capture them. The research team will first confirm in laboratory tanks that they can reliably detect fish densities through eRNA and determine how long the molecules persist in water. They will then test these methods in the Sacramento-San Joaquin Delta, including near water export facilities where young smelt are particularly vulnerable. The researchers will also examine whether they can detect when the fish are experiencing heat stress through changes in their eRNA. Because these smelt species play a vital role in the Delta's food web, better ways to monitor their populations and health could greatly improve conservation efforts.

This project is funded by the Delta Stewardship Council Delta Science Program under Agreement No. DSC23011 and is administered by California Sea Grant.