As fisheries biologists tally their 22nd springtime count of northbound mother and baby gray whale pairs migrating past Point Piedras Blancas on their way to Alaska, scientists are getting a better look than ever at the cetaceans, thanks to eyes in the sky — in the belly of a $25,000 hexacopter, a kind of drone.
With the help of the drone’s photogrammetry, “or pictures we can take measurements from,” the biologists can identify individual whales and accurately estimate the marine mammals’ physical characteristics, according to Wayne Perryman, veteran leader of the Cetacean Health and Life History Program for National Oceanic and Atmospheric Administration’s Southwest Fisheries Science Center.
Developing such aerial photographic techniques has been the focus of Perryman’s research for the past decade or so, as he wrote for his staff profile on https://swfsc.noaa.gov/staff.aspx?id=824.
NOAA biologists, including Perryman, have deployed the photographic drones in other areas of the world, tracking such animals as penguins in the Antarctic, orcas off British Columbia and blue whales in Chilean waters.
But this is the first gray whale counting project on which the team has used the ultrastable, GPS-controlled, six-armed-and-rotored hexacopter with its domed top, digital camera and swim-noodle-like floats (one is neon pink, the other bright yellow, so the pilot can tell at all times which way the device is pointing).
The drone looks a little like a big-bodied, long-legged spider wearing Uggs for skis.
The scientists appear to be giddy-happy with the results, almost like little kids who’d been longing for the new bicycles they just found under the Christmas tree.
How does it work?
Perryman said that, with accurate altitude readings confirmed by landmarks, the scientists use full-length, lip-to-fluke-tip photos taken by the drone’s camera to calculate precise length, width and “robustness” of each cow and her calf. The team also can compare the relationship between the size of a mom and the size and fitness of her calf.
According to hexacopter pilot John Durban, when the small camera is about 100 to 150 feet up, its “normal” f1.8, 50 mm-equivalent lens covers an area about the size of a football field … more than big enough to capture an image of the full length of a 50-foot-long, 30-to-40-ton gray whale cow.
The drone is 22 inches across between the arm-tip rotor motors. Perryman said the hexacopter weighs 2.6 pounds “naked” and 4.5 pounds with battery and camera on board.
The drone’s photos “also show us what size females are reproducing,” he said. “Remember, a cow is not eating while she’s migrating, and she is lactating” to feed her calf, which for a 6,800-mile, two-to-four-month journey, “is a huge drain on her body. … By the time the females get to Alaska, their tanks are empty.” For the mom, “lactating is the most physically expensive part of reproducing.”
The grays aren’t chummy. “There are no social pods” for the bottom-feeding whales, Perryman said. And the males don’t hang around after mating. The Baja California breeding-and-birthing sites are “Club Med for male whales. They provide their services, move on and go back to the bar.”
Eastern North Pacific gray whales are no longer classified as an endangered species. Russian hunters take about 140 grays a year.
With two copters on hand providing redundancy in case of equipment problems, Durban and his ground-crew wife, Holly Fearnbach, are limited only by the Piedras weather and timing — wind, rain, fog and nightfall aren’t safe for flying or productive for taking pictures.
There are rules controlling drone deployment, especially for federal officials flying them over a national marine sanctuary.
Perryman said the stack of permit applications and related correspondence weigh considerably more than the hexacopter he wanted permission to fly.
He needed permits from the Federal Aviation Administration (FAA) to fly the drone, from Bureau of Land Management to fly from the site, from the Monterey Bay National Marine Sanctuary to fly over protected waters, a marine mammal permit and pilot certification by NOAA and the FAA.
“But that’s how it’s supposed to be,” he said. “We have to follow the rules. It’s a good thing.”
For now, Durban said, there are few rules controlling flights by hobbyists, but more — and more stringent — regulations are being drafted.
Studies over time
Perryman said the consistency of the 22 years of annual studies helps scientists connect the dots between whale health, food availability in the Arctic, the depth of spring and winter ice there and how fast it melts, and the effects of predation.
The relationship among those elements “is a balancing act we don’t really understand yet,” he said, agreeing that the relationship is a “head scratcher” for scientists, but for the whales, it’s life and death.
For instance, in Unimak Pass in the Aleutians, the strait linking the Bering Sea and North Pacific Ocean, he said, “About 200 killer whales just wait for the cow-calf pairs to arrive. The orcas get about 30 percent of the calves there.”
But Piedras is a study site of Perryman’s dreams.
He smiled and said, “These whales have the common decency to swim right past our door. We’re doing Arctic research sitting in the California sunshine on our lawn chairs, waiting for the whales to come to us. We can sit here in the sunshine and just count the animals.”
Lisa Ballance, division chief of NOAA’s marine mammal and turtle division (and Perryman’s boss), was on binocular duty April 30. She said she’s “a huge fan of the time series,” in which the same study is done in the same place at the same time every year.
With a big smile, she said, “We’re very excited about the hexacopter” and the photos and data it is providing. “It’s hugely promising, with a huge potential.”
Ballance proclaimed the Piedras study done about 15 miles north of Cambria to be “one of our most valuable, one of the few that allows us to really monitor the productive output” of a species that migrates so close to shore that they literally can be counted. Then the scientists can link the count to “other factors, such as ice conditions in the Arctic.”
She said, “We try to monitor the health of the species and the general environment in which they live.” In doing that, the scientists must differentiate between “short-term changes and chronic ones, such as climate change. … A time series allows us to look back 10 to 15 years or more, providing a context for the triggers” for those changes in the environment and the health of the species.
Early on in the series, the scientists went from pen and paper to computer for the data tracking, but the actual sighting and verification of the massive mammals was then and still is done by sharp-eyed humans.
Huddling behind a temporary plywood wall that shelters them from the wind, the alert scientists spot the passing whales using eyes shielded from the sun by a hand held at eyebrow level, heavy, strong hand-held binocs, mounted binoculars the size of a microwave oven and previously, occasional (because they’re expensive) small-plane or helicopter fly-overs.
This year, team members spot the whales during daytime shifts. If the weather’s right, Durban and Fearnbach launch the drone, which hovers about 100 to 150 feet above the water’s surface until the whales swim underneath. The drone provides video for targeting, and then still photographs, some of which are amazingly clear.
It can be very hard to spot the migrating whale pairs, even though they swim close to shore, often inside the line of kelp. The mama gray tries to hide herself and her baby in the noise of the surf to avoid predators, including orcas and sharks.
That route points their trajectory almost directly at the Piedras point, making it an ideal location from which to count.
Except for the weather.
Wind, fog, rain, choppy seas and clouds can blur the whale’s outlines, making it difficult to tell if what’s been spotted is another kind of whale or marine mammal, the shadow of a cloud or really a gray-whale pair.
Since humpback and other whales also swim in Central Coast waters, the spotters have to be well trained and alert to the differences between the species.
And how are the whales doing this year?
After record numbers of whales were spotted in Baja and Southern California, the 2015 Piedras count looks good, Perryman said May 5 — not record setting, but good.
The team’s initial census estimate of about 1,000 pairs this year is not as high as the 2014 estimate of about 1,500 pairs, but is higher than average.
Perryman said: “The females are looking very robust,” which is a high compliment for a whale, if not for a human female.
“It’s a good year for whales,” the team leader added, “but, with the hexacopter, it’s a great year for the science.”