During the December 2011 cruise aboard the chartered FV Gold Rush, the scientists collected data on the length, age, weight and anatomical features, along with ovaries from 385 female sablefish.
The study is a joint effort led by Jim Stark of the Alaska Fisheries Science Center’s Resource Assessment and Conservation Engineering division, with Katy Echave of the Auke Bay Laboratories division, with support from NOAA’s Alaska regional office.
Although NOAA has been conducting maturity observations on sablefish in Alaska since 1979, the research was always done in summer months when maturity is difficult to assess. By conducting the research in winter, when scientists can clearly identify mature females that will spawn during the next annual spawning cycle, scientists will be able to provide the first accurate estimate of the age that female sablefish become reproductively active, NOAA officials said.
Cara Rodgveller, another NOAA biologist involved in the study, said that mid--December is a good time to sample maturing fish since almost all fish were preparing to spawn but have not yet spawned. Since there is very little knowledge of the winter distribution of sablefish preparing to spawn, Echave placed satellite tags on several individual sablefish to monitor their movements during the spawning season over the next few months.
These tags were set to pop up to the surface in mid-January and February and transmit data to a satellite.
Other fishery scientists will use the information collected during the sablefish cruise to determine the spawning stock size and ultimately set sustainable catch levels for Alaska waters.