Counting fish like a BOSS

Counting fish in the ocean isn’t easy—particularly when they swim among jagged rocks and along undersea cliffs hundreds of feet below the waves. To help, the Monterey Bay Aquarium Research Institute has developed a new camera system called the Benthic Observation Survey System, or BOSS.

The BOSS camera design was fine-tuned, including simulated deployment in MBARI’s test tank, before it was placed in the ocean. BOSS photos ©MBARI

A five-foot metal cylinder that features an array of cameras and lights, the BOSS is designed to be lowered from a ship to the seafloor and land upright on rocky terrain. There, it will help scientists survey fish populations using eight high-definition video cameras.

Researchers and policymakers need this technology to find out more about life in the ocean and how to better protect it. MBARI developed the BOSS with input from investigators at Moss Landing Marine Laboratories and The Nature Conservancy.

“The scientists I’m working with are looking at areas that previously were heavily fished out,” explains MBARI staff engineer Chad Kecy, who led the effort to design and build the BOSS. Chad and his colleagues are trying to get a better understanding of how fish populations are recovering in these areas, what species are present, how big they are and where they swim.

Chad likes the challenge of solving problems on a tight timeline. The BOSS had to be built and tested in a matter of months, because the scientists who planned to deploy it already had research trips scheduled on boats that could not wait.

“Now the scientists are busy analyzing all this video they were able to capture with the tool that we developed,” Chad says.

Mary Gleason, science director for The Nature Conservancy’s California Oceans Program and who helped develop the BOSS, says it can fill important gaps in existing data, based on its inaugural voyage: “We showed that we could get 400 video surveys done across 300 miles of coastline during one three-week cruise. So that’s pretty efficient in terms of data quantity.”

Before the BOSS

The BOSS is the latest innovation in a long line of tools for assessing fish populations. “Prior to these video landers, it was all trawling survey with nets,” Chad says. (Landers are remotely operated systems designed to give researchers the view from the seafloor.)

Bottom trawl nets work well on flat seabeds, but are ineffective for surveying rockfish populations in rocky areas along the California coast.

But nets are impractical in places with rough underwater terrain. Much of the seafloor off California’s coast is characterized by angled boulders, rocky spires and cliffs.

This presented a challenge for researchers studying animals like lingcod and rockfish, which hang out in rocky places. Historically, scientists trawled areas with softer seafloors, and extrapolated the numbers and sizes of fish they assumed were hidden among the rocks.

Over time, deep-sea video emerged as a better way to take measurements.

The BOSS follows an earlier video lander built by Marine Applied Research & Exploration, a California nonprofit. This first-generation lander (“Gen1”, as Chad calls it) used cameras mounted on a swivel, slowly rotating 360 degrees.

The Gen1 Video Lander designed by Marine Applied Research and Education was less effective at documenting rockfish populations in conservation areas. Photo courtesy NOAA SeaGrant

From 2012 to 2015, the Gen1 lander was lowered into the ocean over a thousand times, but it had some limitations. The slow rotation of its cameras occasionally resulted in fish being double-counted. Launching and recovering the Gen1 from a ship could be unwieldy. And its design still had trouble with rocky areas.

So how did MBARI wind up working on the lander’s next iteration?

MARE wanted data on Rockfish Conservation Areas, established in 2002 to curb the overfishing of groundfish, a commercially valuable mix of seafloor species. One is located right by the Monterey Bay Aquarium—an early supporter of California’s first-in-the-nation network of marine protected areas. And the Aquarium is keen on using science to manage the recovery of depleted species, including West Coast rockfish. Besides help from seafood devotees and local fisheries, that effort hinges on data.

Chad and his colleagues knew they could design something better and deliver the data.

The next generation

Like the Gen1 lander, the BOSS uses stereo cameras—two identical cameras side by side, like human eyes. When both cameras record the same fish, they see it from slightly different angles. With proper calibration, it’s possible to determine how far away the fish is, and how big.

MBARI Electrical Engineer Chad Kecy and Mechanical Engineer Francois Cazenave designed the BOSS four pairs of video cameras and a near-360 degree field of view.

The BOSS features four stereo camera pairs, which can film four surrounding areas at once, totaling nearly 300 degrees of coverage.

But the technology wouldn’t function if the lander tipped sideways as it was deployed. So MBARI scientists designed the BOSS to right itself—like a wobbling bowling pin that stabilizes instead of falling over. Its base is weighted with 150 pounds of lead bricks, and the top has 200 pounds of flotation material.

Fisheries researchers often take advantage of opportunities send a BOSS out on already scheduled research trips, so the camera system was designed to be broken down and transported with relative ease. A pickup truck pulling a small trailer is all it takes to haul it.

From Mary’s perspective, standing aboard ship and being able to see what’s going on below in all directions has “just been really fun.” Already, the BOSS has peered not only at many fish but also humpback whales and several species of sharks.

“It’s also a tool that could be used to do rapid assessment in deep habitats for other questions,” she notes. “You could add sensors and do all kinds of other science with it.”

Camera systems allow researchers to document fish populations in rocky areas that bottom trawl nets can’t reach.

At just shy of $200,000 apiece, the BOSS isn’t exactly cheap, but it’s a bargain compared to a lot of other oceanographic equipment, Chad says. The initial results are promising: It’s already brought back more than a terabyte of video—hundreds of hours of fish observations.

Even better, the system may not be one-of-a-kind for long.

This year, Chad and his colleagues plan to produce an operations manual and other documents related to the camera—“everything you would need to replicate a BOSS,” he says.

Production will then head back to the Marine Applied Research and Education team in Richmond, California, where the team expects to start building more BOSS units soon.

—Daniel Potter

Learn more about the Monterey Bay Aquarium’s work to support sustainable seafood.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s