Chinook Salmon In Alaska Tagged For Tracking

A University of Utah study is busy studying Chinook salmon from the Nushagak River in Alaska. Researchers are removing their ear bones that were tagged for tracking to find out more about these fish and where they live and travel. Particular isotopes were placed on the fish as a tracking device. Different isotopes are found in different regions, so the distinct isotope ratios in the layers of the fish bones can show where they were during varying times in their lives, the researchers say.

The special tags have been used on 255 fish and work to trace the fish, starting from the rivers, where they were born to the oceans, where they mature and live for a number of years before going back to their birthplace to spawn, and die.

Salmon Tagged for Tracking Help Researchers Learn More About Them

The tracking device uses strontium isotope ratios to trace the Chinook salmon. This specific element, along with its isotopes is extremely connected to geography, so it works well as a marker, according to study researchers. This is especially true since the geology of Alaska is very diverse with rocks that are categorically different from each other.
They follow the chemical signature that comes from the isotopes on the fish tagged for tracking. Depending on where the fish travel, there are differing amounts of and types of these isotopes that appear in the different areas the chinook salmon live and swim in during their lives.

Data Will Help Study Salmon Numbers, Productivity

The scientists want to see how the salmons’ life and travel in their freshwater stage might affect their seawater stage. All this information will help determine more about salmon productivity and how many fish there are now. The Chinook salmon were all caught and tagged in 2011. The study resulting from this data appears in full in an article in the Science Advances journal. Christian Zimmerman from the US Geological Survey stated that the study is in response to societal issues and the need to learn more about these fish and their habits.

To see more chinook salmon images, check out this gallery.