Bertarelli Summer2024 FINAL - Flipbook - Page 35
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as an aquarist in public aquariums, the past 17
at London’s Horniman Museum & Gardens where he’s the principal curator
of the Aquarium and Living Collection Manager. “Whenever you manage an
aquarium,” he says, “you strive to breed your animals because it shows that
your husbandry is at the level that everything’s healthy.” Soon after arriving at
the Horniman, Craggs began collaborating with coral scientist Mike Sweet at
the University of Derby, and helped set up aquaria to study coral microbiomes
and disease. But, the technologies for coral spawning hadn’t been invented.
So, Craggs turned his attention to jellyfish, which are close kin to corals.
Take a jellyfish, flip it upside down, imagine a skeleton around it, merge a
bunch of those into a colony, and you’ve got a sense of a coral’s anatomy.
Craggs learned to tell if a medusae held eggs or sperm and how to grow jellyfish larvae—and ultimately jellyfish. The breakthrough that allowed him
to breed jellyfish came when he received 20 years of water temperature
data that showed how the jellyfish use environmental clues to spawn. “I was
like, ‘Why don’t we apply this exact methodology to corals?’ ” Craggs says,
“They’re cousins, right?”
Craggs was sitting at his kitchen table reading a Twitter feed from Fiji when
the idea coalesced into a plan. A dive shop there pinpointed the coral spawning so well that they were selling trips to see it. “That tweet got me down this
rabbit hole,” he says, working out “the seasonal temperature, the photoperiod,
the lunar cycles, all of the things that stack up to trigger the coral to spawn.”
On a shoestring budget, Craggs built blackout blinds around the aquaria
that he’d been using for the coral microbiome and disease work. A volunteer
who knew something about IT reprogrammed a microprocessor to mimic
Fiji’s annual cycles of temperature, moonlight, and sunlight. They placed
coral in the system—and waited. Nine months later, in alignment with Fiji’s
reefs, the corals in London released their gametes. “And that literally changed
everything,” Craggs says.
Craggs’ next innovation came, like so many in science, from a mistake. Hoping to expand the project, he teamed up with scientist James Guest working
in Singapore to ship 14 coral colonies to the Horniman. He reprogrammed the
lighting and temperatures in his system to match those in the corals’ native
sea. Spawning was supposed to happen around 9:30 p.m., which made for a late
night, given that Craggs’ workday at the aquarium started at 8 a.m. From Singapore, Guest reported that the corals had released gametes. But nothing was
happening in London.
Craggs kept watching, late night after late night. Finally, exhausted, Craggs
decided to halt the observations. Maybe the travel had shifted the corals’ cues.
Maybe they would spawn following the next full moon.
But the next month, when Craggs checked the corals for eggs, they were
empty. The corals had spawned. “We’d missed the whole lot,” he says. No
one had been watching. “It was the biggest learning curve of the whole process,” he says. “It got me thinking, ‘We’re still thinking like we’re in the field.’
Let’s make sunset happen at half past 10 in the morning. And make the coral
spawn in our working day.”
CRAGGS SPENT 24 YEAR S
33
By 2050, 99
percent of all
corals will be lost
due to warming
ocean waters.
