This is Fish Radio I’m Stephanie Mangini. A fish like fit bit tracks king salmon. Some surprising results after this…
While many scientists are using genetics to determine where king salmon originate others are asking, where have all the King salmon gone? A recent study using satellite tags lead by Andy Seitz a professor at the University of Alaska Fairbanks College of Fisheries and Ocean Sciences is studying just that.
“The project initially was to test using these fairly sophisticated fish tags, which are called pop up satellite tags. We tested them on king salmon to study their movement and behavior, and we targeted western Alaska and the Bering Sea because these are areas with a lot of interest.”   
They have used the tags on halibut and other fish that are similar in size to a king. Seitz says the tags have shown great success.
“What they describe is where fish move, how deep they dive, and what water temperatures they occupy.”

Seven out of twenty-three of the tagged kings reported mysteriously high temperatures. Leading Seitz to believe the tags and the fish were in the bellies of salmon sharks.
“Salmon sharks are a warm blooded animal. Meaning that their guts and their muscle temperature is quite a bit warmer than ambient temperature, and it just so happens that salmon sharks guts are typically about twenty-five to twenty-six Celsius which is what the tags were reading. So that was one of the bigger surprises was the amount of predation by salmon sharks in this study.”   
Seitz’s says he and the team enjoyed the twist in the research.
“It threw us for a loop for a few minutes and then we put it together pretty quickly. But it was a fun part to the study because normally we are used to looking at what a fish does and then the tag pops up and that is the end of the story, but with this we had a little hitch in our story because we were looking at what a king salmon does and then we were looking at what a salmon shark does.”       
A total of 790 days of temperature and light data was recorded within the three-year project. Seitz says it’s too early to draw any conclusions and hopes to get more funding for further research.
“At this stages of our project, we are not able to answer the million dollar question, which is where are the king salmon. What the tags have allowed us to do is formulate feature research questions like how do king salmon behave in the ocean, where do the move, and then with this surprise finding of salmon shark predation it allows us to re-examine some assumptions that people have made about king salmon ecology in the ocean.”
Find links to the “Life and death of big king salmon in the Bering Sea” project at our website