Saildrones Employed to Produce Annual Estimate of Alaska Pollack Abundance

Saildrone wind and solar powered ocean-going robots filled a special need in the midst of the global COVID-19 pandemic to gather data needed by NOAA Fisheries to measure Alaska Pollock abundance in Alaska’s Bering and Chukchi seas.

Data gathered in these surveys every other year is critical to manage Pollock, the nation’s largest commercial fishery. Normally NOAA Fisheries conducts acoustic-trawl surveys from crewed research vessel, but because of the pandemic many research surveys were cancelled. To compensate, fisheries scientist Alex De Robertis at the Alaska Fisheries Science Center developed a contingency plan using Saildrones, which are equipped with solar power acoustic sensors to do the research in the Bering and Chukchi seas.

Three Saildrones used for the survey left California in mid-May and sailed 2200 nautical miles to the Bering Sea. From July 4 through Aug. 20, they worked to collect information to estimate Pollock abundance and oceanographic and atmospheric information for weather forecasting, then sailed back to Saildrone headquarters in Alameda, California.
NOAA Fisheries received the data in mid-October, in time to share with the North Pacific Fishery Management Council, for assessments of stock abundance and trends in the Bering Sea, Aleutian Islands and Gulf of Alaska. The total biomass (weight) of midwater Pollock was 3.6 million metric tons, about 45 percent higher than in 2018, the last time a NOAA research vessel-based acoustic-trawl survey was done. The assessment model combined this survey with other projections of the on-bottom portion of the stock and age structure of the population. Overall, the data indicated that Pollock populations declined by roughly 14 percent from 2019 to 2020.

While not a substitute for the full spectrum of tasks that crewed research vessel surveys can do.

The technology proved to be highly effective in an unusual year, NOAA officials said.

Funds for the project were provided by NOAA’s Office of Science and Technology.