The California Department of Fish and Wildlife is currently conducting an experiment to see which of two types of steelhead trout are the best survivors.
On February 24, both the Central Valley Steelhead and the American River Steelhead were released into the American River at Howe Avenue - each fish having a sensor in its stomach for tracking capabilities.
The American River Steelhead is the traditional trout in the river, however, officials want to see if the Central Valley Steelhead is better at returning in greater numbers when it comes to spawning season.
"They will both be heading to the Pacific Ocean and then returning, however not at the same time, so we want to see which ones return in greater numbers to give us an idea of the survival rate between the two types," Henry Morse, with the CDFW, told FOX40.
The fish are not tracked with the traditional GPS device however the sensor in their belly will be picked up by hidden buoys along the river.
The first round of results are not expected until sometime in 2017.