Fish Monitoring


Fish are an integral part of our environment and natural history. There are millions of acres of lakes, rivers and canals. Our member companies’ biologists work hard to monitor, enhance, and conserve California’s fresh water resources.

Being at the top of the food chain, fish species and fish populations can be impacted through changes in water temperature and composition, such as algae and stream insects, resulting from changes in water quality. Biologists study fish communities to provide insight on California’s fish populations and the condition of the waterways.

Our biologists work hand-in-hand with the California Department of Fish and Wildlife. Monitoring data from ongoing studies contribute to tracking and understanding these water communities.

There are two main activities that our fish biologists perform to monitor fish populations. Movement mapping, or tracking, and mark and recapture. Tracking is a process in which marine biologists and resource managers use technology to tag fish and map their movements. Mark and recapture is a process where a group of a particular fish species are captured, marked or tagged, and then released so they can be recognized during a later recapture. These methods help scientists better understand the numbers and distributions of fish populations.