Shortraker Rockfish Ageing Studies

Shortraker catch on a longline vessel.

We conduct studies to learn more about the life span of shortraker rockfish in the Gulf of Alaska, which are caught incidentally in fisheries including those for sablefish. Due to its large size and bright red color, this species is one of the most valuable slope rockfish in landed price. Annual catches of shortraker rockfish in the Gulf of Alaska have ranged from 500 to 1,500 metric tons since the early 1990s.

Because of its longevity, general lack of biological information, and uncertain biomass estimates in bottom trawl surveys, shortraker rockfish has been managed conservatively in the Gulf of Alaska. Although trends in stock abundance are difficult to discern, catch levels of shortraker rockfish are believed to be well below the level of over-exploitation.

Shortraker rockfish have long been considered one of the most difficult rockfish species for age determination. New aging methods have been developed for shortraker rockfish that for the first time may allow reliable ages to be determined. If reliable ages become available, it may be possible to apply statistical catch-at-age models to shortraker rockfish populations in the Gulf of Alaska. Use of these models would improve our knowledge of abundance trends for shortraker rockfish and help in the determination of appropriate harvest levels.

Contacts

• Rockfish Researchers in Alaska