SAN DIEGO — For the first time, the University of California San Diego’s Birch Aquarium has coaxed a female weedy sea dragon into transferring a large number of eggs to a male sea dragon who could give birth to a bounty of babies.
On Monday, aquarium staff discovered that one of its males is carrying about 100 bright pink eggs in the “brood pouch” on its tail. Many will become fully formed and born in four to six weeks.
Sea dragons, sea horses and pipefish are the only animals on Earth whose males get pregnant and give birth. It is an oddity of nature — and a scientific leap for the Birch.
The aquarium made a tiny bit of progress cultivating sea dragons in 2020, but only now has it had this kind of success.
“I was blown away and started cheering,” said Leslee Matsushige, the Birch’s associate curator.
The Birch first imported sea dragons from the Dallas World Aquarium in 1996 as part of its education and conservation efforts. Getting them to reproduce has been no small trick, mostly because it is hard to replicate the environment of sea dragons, which are best known for silently flitting about in the seaweed beds and rocky reefs of southern Australia.
“We’ve gone through a lot of trial and error, learning how to keep them healthy,” Matsushige said Tuesday. “Most fish will try to reproduce if they are happy.”
The aquarium has done such things as fine-tune the creatures’ diet, adding vitamins and probiotics, and monitoring their calories.
The Birch also tinkered with lighting and rock work to get things just right.
Matsushige said the aquarium will be ready if the pregnant male produces a lot of babies.
