{"id":20297,"date":"2026-09-17T08:00:03","date_gmt":"2026-09-17T12:00:03","guid":{"rendered":"https:\/\/www.autonocion.com\/us\/?p=20297"},"modified":"2026-09-17T05:37:19","modified_gmt":"2026-09-17T09:37:19","slug":"robot-laser-sonar-octopus-garden-bumps-one-map","status":"publish","type":"post","link":"https:\/\/www.autonocion.com\/us\/robot-laser-sonar-octopus-garden-bumps-one-map\/","title":{"rendered":"A 12-foot robot swept a laser 10 feet over the largest known octopus nursery, 10,500 feet down off California, where warm springs hatch the eggs in under two years instead of five to eight"},"content":{"rendered":"

If you watched Planet Earth III<\/em>, there’s a good chance you’ve already seen the Octopus Garden. It’s the hill off Central California where thousands of pale purple octopus sit upside down in the cracks, each mother wrapped around her eggs, and some of that footage came from cameras on a robot run by MBARI, the Monterey Bay Aquarium Research Institute.<\/p>\n

But filming a place and measuring it are two very different jobs. In July, that same robot, the remotely operated vehicle Doc Ricketts<\/em>, went back down with a sensor rig that maps the seafloor to the centimeter. MBARI posted a short write-up of the trip<\/a> on August 3, and it’s a pretty low-key announcement for what’s arguably the most famous patch of deep seafloor in the country.<\/p>\n

So why are there thousands of octopus down there?<\/h2>\n

The Octopus Garden sits 10,500 feet down, at the foot of Davidson Seamount, a dead volcano under the Pacific roughly 80 miles southwest of Monterey. MBARI calls it the largest known gathering of octopus on Earth. The species is the pearl octopus, and it’s roughly grapefruit-sized. It doesn’t go there to live. It goes there to mate, nest and, eventually, die.<\/p>\n

So why that one hill?<\/p>\n

It’s the heat. Water at that depth sits at about 35 degrees Fahrenheit, but warm fluid seeps up through the rock, and inside the cracks where the mothers nest, MBARI has measured water close to 51 degrees. You’d still call that cold. For an octopus, it’s a big deal.<\/p>\n

Octopus are cold-blooded, so their bodies basically run at whatever speed the surrounding water allows. Colder water means a slower metabolism, and it also means a slower-growing embryo inside every egg. At 35 degrees, researchers figured a pearl octopus brood would need five to eight years to hatch, maybe longer. When Senior Scientist Jim Barry’s team followed individual mothers by their scars, the eggs hatched in about 1.8 years, according to the team’s paper in Science Advances<\/a>. That’s a lot less time for a predator to find a clutch of eggs, and frankly it’s pretty smart real estate shopping for a mollusk.<\/p>\n

So what’s the Low-Altitude Survey System?<\/h2>\n

MBARI’s Seafloor Mapping Lab calls it LASS, and it’s essentially three ways of looking at the bottom packed into one sled. There’s multibeam sonar, there’s lidar (think sonar, but with lasers) and there’s a set of stereo cameras. According to MBARI’s project page for LASS<\/a>, the sled flies about 10 feet off the seafloor and can pick out objects under half an inch across. Software steers the robot along the survey lines, not a pilot.<\/p>\n

My favorite thing about LASS is that the laser and the sonar don’t agree with each other. Sound waves go right through soft tissue and bounce off the hard rock underneath. Laser light stops at the first thing it hits. So if you lay the two maps on top of each other, the bumps that only show up in the laser map are, for the most part, animals. On a hill that’s carpeted in octopus, you can see why that’s useful.<\/p>\n

The crew ran four LASS surveys along the Octopus Garden Ridge during a 10-day trip on the David Packard<\/em>, MBARI’s new flagship. Some of that meant flying the exact tracks the lab mapped five years ago, so the old map and the new one can be compared. The rest pushed out past the edge of the nursery, where there aren’t any octopus, to figure out what a crowd that size does to the seafloor around it. They also squeezed in two surveys of Tubeworm Slump, a steep rock wall in Monterey Canyon where clams and tubeworms burrow into the cliff.<\/p>\n

It’s the first time LASS has done science dives on Doc Ricketts<\/em> from the David Packard<\/em>, and it went down with a next-generation lidar, a new system for navigating underwater and software from MBARI’s CoMPAS Lab that tries to spot animals in the images on its own. Doc Ricketts<\/em> also logged its 1,500th dive on the trip. We went through the rest of the robot’s spec sheet last week, when its crew rebuilt a camera’s lights overnight<\/a>.<\/p>\n

\n
\n
Water at 10,500 feet<\/div>\n
35\u00b0F<\/div>\n
Ambient temperature around the Octopus Garden.<\/div>\n<\/div>\n
\n
Inside the nest cracks<\/div>\n
Up to 51\u00b0F<\/div>\n
Warm fluid seeping up through the rock where the mothers brood.<\/div>\n<\/div>\n
\n
Time to hatch<\/div>\n
1.8 years<\/div>\n
Measured in the Garden. Researchers expected five to eight years at 35\u00b0F.<\/div>\n<\/div>\n
\n
Last LASS photo count<\/div>\n
5,718<\/div>\n
Octopus on 6.2 acres in the middle of an 823-acre hill that may hold more than 20,000.<\/div>\n<\/div>\n<\/div>\n

There’s a new generation on that hill by now<\/h2>\n

LASS has flown this hill before, and that earlier survey is where the famous number comes from. The team stitched its photos into one big mosaic covering 6.2 acres in the middle of the Garden and counted 5,718 octopus. The whole hill covers about 823 acres, and MBARI’s estimate for the total population is north of 20,000.<\/p>\n

I can’t find a new count from the July surveys anywhere in MBARI’s write-up. So we don’t know yet how the numbers compare. Still, the biology gives us a decent hint. Pearl octopus die after they breed, and a brood in the Garden takes roughly 1.8 years. Five years later, it’s safe to assume almost none of those 5,718 mothers are still around. Whatever LASS flew over in July is a different crowd, and they’re presumably sitting in a lot of the same warm cracks, since that’s where the heat is.<\/p>\n

That’s why the automatic animal detection MBARI tested might be the most interesting thing on the whole trip. If software can reliably pick octopus out of those images, counting all 823 acres stops sounding crazy. MBARI hasn’t published how well the test went, though, so it’s probably a bit early to get excited.<\/p>\n

Why keep mapping the same hill?<\/h2>\n

MBARI says data like this is meant to help the people who manage and protect deep-sea habitats, and Davidson Seamount and the Octopus Garden are already inside the Monterey Bay National Marine Sanctuary. Barry hasn’t been shy about why that matters. “Essential biological hotspots like this deep-sea nursery need to be protected,” he said in MBARI’s release on the study, pointing to mining, fishing and climate change as threats down there. A before-and-after map sharp enough to show individual nests is tough to argue with.<\/p>\n

If you’re wondering why anyone needs a map this fine-grained, MBARI points out that only about a quarter of the seafloor is mapped in enough detail for scientists to actually use.<\/p>\n

The July mapping also had a more immediate job. Its data was meant to guide the next David Packard<\/em> cruise, which went back to Davidson Seamount from August 3 to 12 with Barry as chief scientist. MBARI President and CEO Antje Boetius rode along, and in her August 11 log she wrote that Doc Ricketts<\/em> needs about an hour and a half to get down there and another hour and a half to come back up. That leaves you roughly six hours to work on the bottom. She also describes a dense cluster of mothers known as the “Octopus Spa.” Honestly, that’s a better name than most things in science get.<\/p>\n

MBARI’s plan for that cruise included a time-lapse camera shooting a patch of about 50 brooding mothers roughly every half hour for a year, to follow the whole cycle from the day eggs get laid until they hatch. Barry’s final log is mostly about listening for beaked whales near the seamount, so I haven’t seen MBARI confirm in writing that the octopus camera went in. The log does say they’ve left instruments on the seafloor, and a few of those will keep logging data for a full year.<\/p>\n

In Barry’s last log from the cruise<\/a>, posted August 12 as the David Packard<\/em> headed back to Moss Landing, he says the team’s planning to come back next year to haul up its moorings and pick up its observations where it left off.<\/p>\n","protected":false},"excerpt":{"rendered":"

If you watched Planet Earth III, there’s a good chance you’ve already seen the Octopus Garden. It’s the hill off … <\/p>\n

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