ALL ISSUES     |     SPRING 2018
Chambered nautilus hatchling at the Monterey Bay Aquarium

Extended Story

Exploring a Chamber of Secrets

(continued from What's New)

No one, for example, has seen a nautilus egg in the wild—perhaps because they're laid at depths beyond where recreational scuba divers can safely go. Nautilus can range below 330 feet deep (100 meters)—but do the young develop in warmer waters, closer to the surface, or in cooler, deeper waters?

These are some of the unknowns Ellen contends with as she tries to take the rearing of chambered nautilus beyond the point her colleagues have achieved.

As a member of the team that cares for the animals in our Tentacles special exhibition, Ellen raises many of the species we exhibit, including cuttlefishes and squid. She and her teammates have built a successful track record with species that no other aquarium had raised before.

The chambered nautilus presents an entirely new set of challenges, which Ellen's been wrestling with since the first nautilus egg hatched in late July in 2017. Several others have hatched since then.

Colleagues at Waikiki Aquarium, Henry Doorly Zoo and Aquarium and Birch Aquarium have hatched and raised chambered nautilus. None of the hatchlings survived much more than a year.

Toba Aquarium in Japan has also successfully hatched chambered nautilus, with a few individuals surviving three years or longer—including one that lived four and a half years.

After that, the animals died, for reasons unknown, Ellen says.

"When I asked my colleagues what happened, they all said: 'We have no idea. They became buoyant in the water column and stopped eating.'"

Aquarist Ellen Umeda observes adult nautilus at the Monterey Bay Aquarium
Aquarist Ellen Umeda observes adult nautilus at the Monterey Bay Aquarium.

Ellen has the benefit of their experience, knowing the water temperatures at which the hatchlings were raised, and what was in their diet.

"They all got to a certain point," she adds. "Now I'm asking: 'What can we do differently?'"

It's an approach that's worked well for us in the past. Our aquarists were the first to culture several species of jellies; consistently raise multiple generations of comb jellies; and exhibit young white sharks, get them to take food while on exhibit, and successfully return them to the wild.

The opportunity to work with new species is built into the foundation of the Aquarium, says Vice President of Husbandry Jon Hoech.

"When the Aquarium was first being planned, David Packard and the other founders visited many other aquariums," he says. "Each time they asked, 'If you could do it all over, what would be different about your facility?' One of their takeaways was: Include more behind-the-scenes space for the animal care staff to work. So, we have room in our galleries to raise animals before we know we'll be able to keep them on exhibit."

Another piece of the foundation came from our original husbandry director, David Powell, Jon says.

"Dave insisted that our aquarists have time in their schedules to work on projects, and not just have their days filled with routine maintenance of our living exhibits," he says. "They're encouraged to try new things and take risks. That's why we've been able to bring so many new species to the public, year after year."

Ellen is drawing on the experience of colleagues at other aquariums, and the resources here in Monterey, to seek a breakthrough in chambered nautilus care.

Ellen's childhood journal entry
As a child growing up in the Bay Area and visiting Monterey, Ellen charted her hopes and dreams in a journal, including this entry: "When I grow up, I want to work at an aquarium."

She is now caring for more than 150 nautilus eggs, and a few hatchlings. They're housed behind the scenes under low-light conditions, some in cooler water and some in warmer.

She's experimenting with the water temperature at which she's keeping the eggs laid on exhibit by the adult nautilus. And she's working with Curator of Collections Joe Welsh, who's pioneered the use of pressurized holding tanks for deep-water species.

Ellen believes raising chambered nautilus under pressure—perhaps even putting eggs in a pressurized aquarium before they hatch—could be the key to solving the problem of the young nautilus becoming buoyant in the water column, rather than neutrally buoyant and able to maintain their position in the water.

She thinks that the fluid-filled chambers that develop, section by section, in a growing chambered nautilus may not function properly unless they form under pressure.

"Some of my colleagues thought that might be a solution, but they didn't have the resources to pursue the idea," she says. Here, she noted, we have a track record of success with deep-water rockfishes that may point the way forward with chambered nautilus.

"We need to experiment and try different things that mimic their environment in the wild, things that other people haven't done," Ellen says. "I hope our animals will live longer, and that a greater percentage of them will hatch and survive. The ultimate goal would be to raise them to adulthood, have them lay eggs, then raise the next generation."

That, she admits, is probably a long ways off. Just as she's benefitted from the experiences of her predecessors, she hopes to contribute the next increment of progress.