SAN DIEGO — Staff at Birch Aquarium at Scripps Institution of Oceanography at the University of California, San Diego, are hoping a pregnant male sea dragon will produce many babies.    

What You Need To Know

  • Birch Aquarium is monitoring a rare pregnant male Weedy Seadragon

  • Like seahorses, seadragon males — not females — are responsible for carrying eggs

  • It is extremely rare for Seadragons to breed in captivity

  • Weedy seadragons are found only in Australian coastal waters

In what is an extremely rare occurrence, Birch announced the first successful transfer of eggs from a female seadragon to a male in the Seadragons & Seahorses habitat, which opened in May 2019. It is one of the largest seadragon habitats in the world, designed to create an ideal environment to breed seadragons.

“It was a joyous day and full of excitement because it was almost unbelievable,” associate curator Leslee Matsushig said. “I had to come here that day even though it was my day off to see it!”

Like seahorses, seadragon males — not females — are responsible for carrying eggs. An egg transfer is quick, but occurs only after the seadragons participate in an elaborate courtship “dance.” The male and female mirror each other, often with their tails curled away from their mate, and spin together snout-to-snout, moving up and down in the water column. This dance is essential for the successful transfer of eggs from the female onto the male’s tail, where he then fertilizes and hosts the eggs.

Marine biologist Greg Rouse said while there is no guarantee all the eggs will hatch, he’s hopeful at least some will.

“It’s a long journey to get this to work in a regular fashion,” Rouse said. “There’s a bit of a mystery about really how to make the breeding happen regularly, but the environment here clearly has worked.”

Rouse is a scientist at Scripps Institution of Oceanography, and they partner with Birch to study Weedy Seadragons both in the wild and at the aquarium to alleviate pressure on wild populations.

Endemic to southern Australia, Weedy Seadragons face challenges in the wild, including climate change, warming oceans and compromised habitats.