August 16, 2018 — There’s something unusual going on with the sockeye salmon runs returning to Alaska this year. In some places — like Bristol Bay — the runs are strong. In others, like the Copper River or the Kenai River they’re unexpectedly weak. In some places, there are sockeye that are unusually small. In others, sockeye of a certain age appear to be missing entirely.
It’s a mystery.
In Southeast Alaska, one of the first Fish and Game staffers to notice an unusual trend was Iris Frank, a regional data coordinator and fisheries technician.
Frank’s lab is on the first floor of Fish and Game’s Douglas Island office that looks like it hasn’t changed much in the 32 years since she got there.
Frank has been looking at blown-up images of sockeye salmon scales for decades. She pops one onto the machine and dials it into focus to show that salmon scales have ridges, called circuli. They look a lot like fingerprints.
Circuli carry a lot of information about what a salmon has been doing since it hatched.
“So if you think about a fish being out say, in a lake in the summertime, it’s warmer there. There’s more feed around. So these circuli are probably going to be bigger and more widely spaced apart,” Frank said.