The rockfish caught near Sitka last month was not 200 years old, but a different fish caught near Ketchikan was over 100 years old.
The Department of Fish and Game lab in Juneau received two otoliths from two different fish. An otolith is a bone found within a fish’s ear that contains annuli, similar to rings on a tree. Scientist use otoliths to determine the age of fish
The shortraker caught off Kruzof Island near Sitka last month was suspected to be 200 years old, which is five years shy of the record age for a rockfish.
Kara Hilwig is the lab supervisor for the age determination unit. She says the 41-inch, 39-pound rockfish was not that old.
“This particular specimen was interesting in that it represents what we typically see as what we call a ‘fast growth specimen,’ so even though it was really long, it was quite young, so it grew very, very rapidly. We aged that fish to be 64,” Hilwig says.
The circumference of the otolith from the hexagenarian Sitka shortraker was the size of a quarter, but it wasn’t thick. Hilwig compares that otolith to the one found inside another shortraker caught in West Behm Canal near Ketchikan last month.
“It was a smaller circumference on the otolith but it was really thick and heavy. It sounded like a glass marble when you dropped it on the table, whereas the otolith of the fish that came out of Sitka sounded more like a paper clip.”
The otolith from the Ketchikan shortraker revealed the rockfish to be 120 years old.
That fish was 39 inches and nearly 30 pounds – two inches shorter and ten pounds lighter than the Sitka fish half its age.