The NOAA Fisheries' Northwest and Southwest Fisheries Science Centers are testing the first use of autonomous, wind and solar-powered vehicles, or saildrones, to gather essential data on West Coast fish populations. Beginning in June 2018, four saildrones will duplicate the path of the NOAA Fisheries ship Reuben Lasker as it collects data on populations of sardine, anchovy and other small fishes, to also survey hake, a deep-water species that is one of the West Coast's most valuable commercial fisheries. A fifth saildrone will explore different approaches to improving the accuracies and efficiencies of future stock assessments. The four-saildrone mission will run up to 100 days, and the fifth saildrone may be deployed for up to six months.
On Sunday July 8, 2018 the two southern survey area Saildrones were launched bring us up to four vehicles on our coast-wide survey. Since the first two new 5th Generation Saildrones have been faster than we anticipated we are starting the second pair further north than we originally planned and tasking them to complete additional transects. This will give us the additional benefit of overlapping transects between the Saildrones pairs. By completing this coast-wide survey using four Saildrone Unmanned Surface Vehicles (USVs), we are learning about differences in survey planning for the USVs and the conventional research ships. Changes in thinking on where we start transects at sunrise have led us to begin in the middle of the transect for each Saildrone pair and direct the Saildrones to work away from each other. This allows them to maintain station overnight mid transect rather than one being in the nearshore area, which is subject to more vessel traffic and nearshore wave action. Simple changes that make operations easier and safer.
Our survey design has each transect covered by a pair of Saildrones. Transects are run perpendicular to the Continental Shelf break, nominally in an East-West direction (Figure 1a). Transects cover a bottom depth range of 50 to 1500 m or 35nmi, whichever is greater. Due to the diurnal migration of Pacific Hake and Costal Pelagic Species (CPS), such as sardine and anchovy, we only conduct acoustic survey operations from sunrise to sunset. During daylight hours the fishes are in deeper, tighter aggregations making them easier to assess acoustically. At night these aggregations disperse and rise in the water column. The Saildrones will survey these evenly spaced transects by running east-west then transiting south to the next transect. Think of it as mowing your lawn, you go across in one direction then turn and move over a set distance and head back the other way. Because the Saildrones are working in pairs they will mow the lawn by starting at opposite ends of the transect, meet in the middle , then head south to next transect overnight, from the midpoint of this new transect they work away from each other to transect ends. They will repeat this alternating pattern for the duration of the approximately 100-day survey until all transects have been acoustically surveyed.
Saildrones began our first survey transect, 126, at the north end of Vancouver Island (Figure 1). Wind speed and direction are better than we anticipated so we were able to complete the transect with a single drone, 1027. Saildrone 1028 was a little behind 1027 so they will meet in the next transects and begin paired survey operation. It is exciting to be starting our work, we have high hopes for this project!
Overnight the Saildrones transited south to the midpoint rendezvous on transect 124. At sunrise they began survey operations from the transect midpoint and head away from each other. We are near the NOAA Ship Reuben Lasker, which is conducting the annual Coastal Pelagic Species Survey. The Saildrones are running the same transects as the ship and the two sets of acoustic data will be compared at the end of the project.
Thanks to videographer John Gussman of Sequim, Wash., for documenting the launch of the first Saildrones and enjoy his video, shot in part by an aerial drone, describing the ambitions and goals of the mission. The day was perfect for a launch, clear and blue, and the Saildrones are safely on their way to the north end of Vancouver Island, where they will start following transects on their way south toward California.
Check out the video here!