In early September, aquarists at Birch Aquarium at Scripps Institution of Oceanography (BAS) at UC San Diego anxiously awaited the arrival of a private plane at San Diego’s Montgomery Field.
The plane was carrying three weedy seadragons, unusual fishes related to seahorses that have appendages resembling seaweed, which act as camouflage in their natural habitat. One of the seadragons delivered that day was an exciting first for the BAS aquarists – a male carrying a clutch of eggs on his tail.
Transporting a weedy seadragon male carrying eggs can be very risky. It was unknown how it would react to the stress of transport.
“I was so nervous, I even tracked the plane the whole trip,” said aquarium co-curator Leslee Matsushige.
Matsushige had reason for her nervous anticipation. Weedy seadragons are among the most difficult marine fish to breed in captivity. Only a handful of aquariums in the world have successfully bred and raised them.
The weedy seadragons are a donation from the Monterey Bay Aquarium, where an exhibit showcasing these fish was closing. The careful transfer of the animals was a collaborative effort between the two aquariums. The aquarists were concerned about transporting the egg-carrying male on a lengthy car trip. Instead, he and two of the larger seadragons were carefully packed into shipping bags in coolers at the Monterey Bay aquarium early one morning, and flown to San Diego in a plane piloted by former Scripps marine technician Eddie Kisfaludy. The smaller animals were later packed and driven between the two aquariums on their own.
The animals were brought to a breeding lab in a quiet room adjacent to the Birch Aquarium’s popular public seahorse and seadragon exhibit. Aquarists built the space with help from a donation from the Lowe Family Foundation. The breeding lab was constructed with great attention to detail. Before designing the lab, Matsushige traveled to the southern coast of Australia along with Scripps Professor Greg Rouse to observe seadragons in the wild.
“Healthy adults will have healthy babies,” Matsushige said, “so right now we are focusing on the health of the adults, which includes giving them nutritious food and a quiet setting that resembles their natural environment.”
The lab contains a 2-meter (6-foot) deep tank, giving the animals ample space. Seadragon breeding is seasonal, and usually happens at night, so aquarists adjust light and temperature to mimic seasonal cycles. Because the lunar cycle is also important in fish breeding, at night the lighting in the lab mimics the monthly phases of the moon.
The breeding program will be a collaboration between BAS aquarists and Rouse’s laboratory. Josefin Stiller, one of Rouse’s graduate students, is examining the genetic diversity of the aquarium’s seadragon population in order to eliminate inbreeding and ensure the health of the new seadragon populations.
Once experienced with weedy seadragons, the team hopes to also breed leafy seadragons. “Leafies” are spectacular animals with even more elaborate seaweed-like appendages. They are closely related to weedy seadragons, but have a much smaller geographical range, so they are far harder for aquariums to acquire. BAS hopes to be one of the first to breed leafy seadragons in captivity.
The hard work of the Monterey Bay and Birch aquarists has been successful – all of the animals are doing well. The egg-carrying male retained his entire clutch, and the eggs have been visibly developing. On September 19, one of the eggs hatched and the baby, although premature, is now living on its own. Matsushige expects the rest of the eggs to hatch in the last week of September, an exciting start to the BAS seadragon breeding program.
The aquarium hopes to be able to supply seadragons to other aquariums, which will limit the number of animals taken from the wild. The stunning fish are a powerful way to connect aquarium visitors to life in the oceans.
“Every day when I am working at the exhibit, I love watching visitors’ amazed reactions to the seadragons. Many have never seen anything like them before,” said Matsushige.
– Kelley Gallagher is a fifth-year student with microbial ecologist Paul Jensen.