The Cooperative Aging Project (CAP) provides direct support for U.S. West Coast groundfish stock assessments by aging 20,000 to 30,000 fish per year. Ages are determined by examining a fish's otolith, or ear bone. Otoliths accumulate annual layers that can be counted similarly to tree rings.
These ages are critical for understanding rates of fish growth, year-class strength, and the vulnerability of each stock to fisheries and survey monitoring.
Aging specialists also collaborate with stock assessment scientists and staff from other aging labs to improve current aging methods, evaluate alternate aging approaches, and better understand the uncertainty associated with age determination.
The program is funded by FRAM through a grant to the Pacific States Marine Fisheries Commission, and is housed at the Hatfield Marine Science Center in Newport, Oregon.