Huge Shortraker Rockfish Delivered to FMA Wet Laboratory
Figure 1. AFSC scientist Chris Wilson with shortraker rockfish and 38-inch ruler in the FMA wet lab. Photo by Karna McKinney.
Observers identify and collect biological information from various species found in the Bering Sea/Aleutian Islands and Gulf of Alaska during their deployments. The majority of the biological data collected falls well within the expected size ranges and species distributions for a particular area.
On occasion, something different is found in the catch. This quarter, a particularly interesting specimen was delivered to Fisheries Monitoring and Analysis Division (FMA). Michael Myers, the factory manager of the catcher processor trawl vessel Kodiak Enterprise, delivered a huge shortraker rockfish (Sebastes borealis) (Fig. 1) that had been caught by the vessel north of Unalaska Island.
Shortraker rockfish are the largest rockfish of the genus Sebastes found in Alaskan waters. The maximum length reported for shortraker rockfish in the North Pacific Ocean is 120 cm fork length. It is estimated that the species reaches maturity at 9 – 12 years. The species has been aged up to 157 years and is among the longest-lived fishes in the oceans.
This particular fish was caught in a pelagic trawl targeting walleye pollock in approximately 350 fathoms (640 m) of water. The specimen weighed 26.7 kg, was 112 cm long, was female, and held eggs in the late developing stage (vitellogenesis). The gonads and stomach were collected by the AFSC Fishery Interaction Team for later analysis. The otoliths were removed for analysis by the AFSC Age and Growth Program; their work on this specimen is also addressed below.
Mr. Myers spotted the shortraker rockfish among the catch of pollock along with other large, but not quite as large, red rockfish. (These fish were dead when brought on deck.) The specimen was not part of the observer’s sample so Mr. Myers collected the specimen himself. After taking the rockfish to his children’s school where it delighted both students and faculty, Mr. Myers brought the fish to the FMA wet lab for our use. Many AFSC staff members enjoyed the opportunity to view this unusually large specimen.
Figure 2. Observers and UW graduate student identify fish in the FMA wet lab. Photo by Brian Mason.
Specimens brought in by observers and the fishing community support the FMA teaching collection. The FMA collection of fish, crab, and bird specimens is essential to the observer training program. The FMA Division and the University of Washington (UW) collaborate in training; the UW has provided graduate students to conduct species identification training and curate the teaching collection (Fig. 2). This arrangement provides quality fish identification training for observers through lectures on key identification characteristics and laboratory sessions with the trainer. Initial training and periodic follow-up briefings include species identification exercises to ensure observers are skilled in specimen identification and in recognizing when a specimen should be brought to the lab for verification and documentation.
Unique, rare, or out-of-range specimens brought to us are identified through the combined expertise of AFSC and UW staff. These specimens are often added to the UW Fish Collection where over 500 specimens representing 189 species collected by observers are cataloged. Further information on the UW Fish Collection is available on the web at
http://artedi.fish.washington.edu/.
Two specimens collected by observers were an important contribution to recent research at the UW on deep-sea anglerfish (suborder Ceratioidei). One of these specimens was a rarely seen female with an attached male. Additionally, observer collected specimens have contributed to range extensions of North Pacific fishes such as Aleutian scorpionfish (Adelosebstes lateens) and gray rockfish (Sebastes glaucus).
Time spent at sea provides observers and fishers alike with unique opportunities to collect specimens that contribute to the knowledge of the fish, crab, and birds that inhabit the Bering Sea/Aleutian Islands and Gulf of Alaska regions. Through our working relationship with the UW, FMA provides observers the training to recognize and collect needed specimens contributing to our overall scientific knowledge. This work is supplemented through helpful contributions from members of the fishing industry as noted above.
