Landmark West Coast Survey Assesses Fish Stocks, Counts Marine Mammals, and Collaborates with Saildrone to Test New Technologies

Image of NOAA Ship Reuben Lasker floating in the distance behind an orange saildrone floating in the foreground
NOAA Ship Reuben Lasker and Saildrone off the coast of California. Photo credit: NOAA Fisheries/Chris Hoefer

NOAA Fishery Survey Vessel Reuben Lasker and a small fleet of unmanned, instrumented saildrones wrapped up nearly 5 months of research this week after crisscrossing waters off the West Coast in a landmark survey of species ranging from krill and anchovies to whales. Scientists also collaborated with Saildrone, Inc.The previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries disclaimer to test the unmanned surface vehicles as an affordable way to augment ship-based sampling.

Scientists will be analyzing data from the 2018 California Current Ecosystem Survey for months to come. The effort successfully tested new technologies while also gathering population and distribution data for marine mammals and seabirds, as well as their migratory prey such as krill, sardines, and anchovies.

“This was the first survey of its kind off the West Coast in terms of looking at all these species at once,” said Jeff E. Moore of NOAA’s Southwest Fisheries Science Center in La Jolla, California. Moore led the marine mammal portion of the survey. “We’ll be able to study in some detail the association of different marine mammals with prey, and get a better understanding of how predators may be affected by changes in the prey landscape.”

NOAA Fisheries conducts regular stock assessments to gauge the populations of multiple species of fish and their natural predators off the West Coast, and ensure that fishery harvest levels remain sustainable. Separate surveys normally are used to target predators and prey, but in this case scientists used Lasker’s sophisticated echo sounders and other technology to gather data on several commercially and ecologically important species at once.

The survey was a joint effort between NOAA ’s Southwest and Northwest Science Centers, Cascadia Research CollectiveThe previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries disclaimer and Saildrone, Inc. of Alameda, California. Saildrone has developed seagoing instrumented drones that can operate autonomously for up to a year in a wide range of conditions. In addition to the Southwest Fisheries Science Center’s evaluation of saildrone data for surveys of pelagic fish species, the Northwest Fisheries Science Center evaluated the data for assessing hake, also known as whiting, which supports one of the largest commercial fisheries on the West Coast. Because Lasker and two saildrones crossed into Canadian waters, Fisheries and Oceans Canada was also a partner in the effort.

Northwest Fisheries Science Center research scientist Larry Hufnagle, who helped lead the surveys for hake, said the saildrones proved responsive and robust, with great potential to improve NOAA stock assessments. “We’d like to keep working on this partnership, as we think it’s very promising,” he said.

In total, five saildrones added to Lasker’s data-gathering capabilities, traveling a total of more than 18,500 nautical miles over the course of the summer. Four of the autonomous vehicles traced transects along the West Coast from the north end of Vancouver Island south to Southern California, collecting information on fish populations to compare to similar data gathered by Lasker. This will help scientists determine whether data collected by drones can bolster Lasker’s data to improve the efficiency, precision, and accuracy of stock assessments.

A fifth saildrone explored more specific areas of interest, such as shallow waters close to shore that large NOAA research ships cannot safely navigate. This drone will remain at sea until at least February 2019 to collect data on anchovies and other fishes that seasonally migrate from their summer feeding areas north of Point Conception to their winter and spring spawning grounds off Southern California.

Aboard Lasker, scientists surveyed marine mammals and seabirds to support population assessments used by fisheries managers to assess risks to whales and other protected marine mammals. Because of this focus on coastal fish stocks, Lasker spent much of its time over the Continental Shelf, where the fish stocks are concentrated and where marine mammal densities are higher as they gather to forage.

Collaborating researchers from Cascadia Research Collective conducted small boat operations to collect biopsy samples and photographs which will be used for stock determination, primarily of large whales in nearshore waters.

The survey documented record numbers of marine mammal sightings, including more than 1,400 groups of marine mammals, from blue whales to common dolphins, and more than 600 humpback whale sightings. This total surpasses all previous marine mammal surveys conducted by the Southwest Center.

One morning in August during the survey, observers on Laskersighted more than 20 groups of marine mammals in just 40 minutes. The area was rich with anchovy, and humpback whales and Pacific white-sided dolphins accompanied by seabirds streamed by the ship. The combination of marine mammals, seabirds, and schools of prey fish detected by acoustic sensors illustrates the close linkages between marine predators and prey, Moore said.

Researchers aboard Lasker also deployed floating acoustic monitors called "DASBRs" (Drifting Acoustic Spar Buoy Recorders) to help detect deep-diving animals such as beaked whales and sperm whales. The recorders pick up underwater sounds that, when retrieved and analyzed, can help determine the size and extent of populations of less-visible species.

The sighting data for marine mammals combined with the population data for the fish and krill they consume should help scientists better understand the potential impacts of predators on fish populations.

“This survey was novel because it combined observations of zooplankton, fish, marine mammals, and seabirds throughout the California Current Ecosystem,” said David Demer, who led the survey of pelagic fishes and krill. “In this way, we may be able to directly estimate the amount of fish and krill consumed by their natural predators. We also learned some ways that saildrone technology can sample where, when, and how the ship cannot effectively or economically sample.”

Learn more:

Fisheries Resources Division, Southwest Fisheries Science Center

Marine Mammal and Turtle Division, Southwest Fisheries Science Center

Fisheries Resources and analysis Division, Northwest Fisheries Science Center

Watch the West Coast Saildrone Fisheries Mission VideoThe previous link is a link to Non-Federal government web site. Click to review NOAA Fisheries disclaimer- 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.