Sea Dragons Sharing Secrets in Captivity
Kerry Hall based on reporting by Robert Kovacik
National Geographic Today
|August 13, 2002|
A year after Big Daddy and Poppa Dragon gave birth, their fragile babies
are thrivingand researchers are steps closer to better
understanding this species.
Big Daddy and Poppa Dragon are weedy sea dragons, delicate creatures that look like twiggy tendrils of seaweed, no more than ten inches (25 centimeters) long, and who live at the Long Beach Aquarium of the Pacific near Los Angeles. Sex roles are reversed in sea dragons. The males become pregnant after the females deposit their eggs onto them. When Big Daddy and Poppa Dragon became proud fathers last year they set a world record: It was the first time that sea dragons in captivity had successfully given birth. Big Daddy had 15 babies that survived; Poppa Dragon had 25.
Relatively little is known about the small aquatic animals, which with their elongated bodies and snouts look like miniature versions of their namesakethe dragon. For example, scientists don't know how long sea dragons tend to live. They don't know how old sea dragons must be to reproduce. And they don't know how to identify the boys from the girlsuntil they start to mate.
But the sea dragon toddlers could change this.
"There's not a lot of real scientific information on these animals that has been published before," said Kristy Forsgren, who manages the sea dragon and sea horse exhibits at the aquarium. "Having them actually breed and watching them grow up, we're able to learn a little more about their reproductive biology and see the whole life cycle in an aquarium."
Scientists haven't had much luck studying sea dragons in the wild because they are increasingly rare. A type of pipefish, sea dragons are native to the kelp forests of the coastal waters of Australia. They have leaf-like appendages that enable them to hide among floating seaweed or kelp beds. They feed on crustaceans, such as the small shrimp-like mysids. They are also fragile creatures, sensitive to changes in their environment. Pollution, urban run-off, and temperature change can kill them. They are even protected by the government in their native Australia.
So researchers are counting on the captive sea dragons to shed light into their mysterious lives.
Sea dragons have only been in captivity for 15 years. There are two kinds of sea dragons: weedy and leafy. The Long Beach aquarium, which opened in 1998, acquired Big Daddy when he was 6 months old. Today, the museum has seven weedy sea dragons and 12 leafy sea dragons. Of the seven weedy ones there are three males, one female and three babies whose sex has yet to be determined.
The sea dragons mated last year with only little help from the aquarium staff.
Because they are extremely sensitive to their surroundings, Forsgren adjusted their water temperature and daylight to match that of the changing Australian seasons. Once springtime conditions hitlove blossomed.
"It was all up to them," said Forsgren, who has managed the sea dragon exhibit for two years. "They just decided they were going to mate and reproduced. I don't understand the dynamics involved in who it was who mated. I just came in one day and they decided to mate."
"They pretty much run the show."
During mating, the female produces bright pink eggs, which she transfers to the male. The male then carries them on the underside of his tail for about four to six weeks. Once they are born they are independent.
Big Daddy gave birth first, followed by Poppa Dragon.
Babies Scattered Across the Continent
Of the 40 babies thriving today, all but a handful were sent to live in aquariums across North America so others could study and breed them.
North American aquariums were chosen because Forsgren and others at the Long Beach aquarium didn't know how to transport the fragile newborns. And they knew it was precious cargo. "These guys do not have another species in their genus," Forsgren said. "If we lose these animals, then we will not have a lot of information about what these animals were or how they evolved or who their ancestors were."
For now, Forsgren is waiting to see when her babies might mate. She guesses that the sea dragon's life span is five to seven years, but she doesn't know for sure. The sea dragon toddlers look a little too small to reproduce now, she said.
But maybe next year.
"It's very exciting to watch the animals grow," she said. "Every day we learn a little more."
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