Northern California's Chinook salmon population has been declining for years. it was so bad this year that, for the first time, regulators banned all ocean fishing of Chinook in California and Oregon.
But scientists are now launching a high-tech effort to help the fish make a comeback.
Bins floating in the Sacramento River contain more than 5,000 baby salmon.
They're no ordinary Chinook salmon. Tiny transmitters were implanted in their tummies on Thursday, so scientists can track them as they make their way to the San Francisco Bay.
Sixty underwater listening stations will track them as they pass by and this unmanned robotic boat will gather data about the currents at the same time.
U.S. Geological Survey hydrodynamics John Burau says a robot is the way to go for a study like this one.
"We plan on running that thing as I said probably 20 days for 24 hours a day. So having people at night running around in boats, in the fog with barges going around is a bit dangerous. This thing can get hit bad, but no one dies," said Burau.
Scientists are trying to learn more about why some salmon survive and others don't, and learn more about why the fish choose one route over another.
The Department of Water Resources hopes this knowledge will help them turn around the declining Chinook population, and that this high-tech approach is only the beginning.
"My vision is 30 to 50 years from now we will have instruments that are out 24/7 when we have a simpler way of tagging the fish and deploying them to allow us and give us better information and a real time basis," said Victor Pacheco from the Department of Water Resources.
A team of biologists surgically implanted the transmitters in assembly line fashion -- a minute and a half per fish.
"The tools that this study will generate I think are going to be amazing and really powerful and more so than a lot of other things that have been done in this systems. So I think that's what's most exciting to us is that it will matter," said Marty Liedtke from USGS.
It will take the fish two to three months to get to the San Francisco Bay. The data will be gathered for four months, but it will be a year before all the results and analysis are in.
To learn more about who this hi-tech procedure works, click on The Back Story