Pregnant Male Fish Could Make Aquarium History
By Wednesday, the signs of pregnancy were clear: bigger appetite, the need for some pampering, the fertilized eggs riding low . . . under Big Daddy’s tail.
Barely impregnated and resembling a twiggy, prehistoric bird, Big Daddy the weedy sea dragon was presented for his close-up at the Aquarium of the Pacific in Long Beach. He had made “husbandry history.” His due date? June 15.
The rare and successful transfer of eggs from female to male weedy sea dragon transpired somewhere in the shadowy 1,500-gallon tank after closing Friday night. The next morning, aquarium curators rejoiced after they found 8-inch-long Big Daddy laden with 75 eggs stuck like tiny pink pearls to the swollen underside of his tail.
The weedies have never bred in captivity, and this is only the second time at a North American aquarium that the fragile eggs have been exchanged, experts say. The first occurred at the Long Beach aquarium last June, but there were no survivors.
“We know so little about them that to have this happen a second time is just--it’s so thrilling,” said a beaming Sandy Trautwein, curator of fishes and invertebrates for the aquarium.
“To those of us who do sea dragons, it’s a pretty big thing,” added Paula Powell, Dallas World Aquarium curator of animal husbandry. “It’s a really big step toward understanding these creatures. As of 1995, Dallas World was the only aquarium in the world to have even been able to keep sea dragons alive” in captivity.
Sea dragons are among only five fish groups in which the males incubate the eggs. Much is unknown about their reproduction--there is no known witnessing of the egg transfer--but curators have observed an elaborate courting ballet in which he and she dragons circle each other. The female drops her eggs, which appear attached like grapes on a vine. After that, curators think, the female somehow lays the 1/4-inch eggs on the now-swollen tail of the male, which fertilizes them.
Kin to the sea horse, the weedy sea dragon is native to a small area of coastal Australia, where it and other sea dragons are a protected species, curators say. Little is known about them because they live in kelp forests and blend with their look-alike scenery. In addition, not many divers want to spend much time in the relatively cold waters they inhabit, Trautwein said.
So protected are the sea dragons that curators say there is one man in all of Australia who has a permit to collect the pregnant males--after the egg exchange and on the verge of their due date. He then cares for the babies and releases the fathers back to the sea. Besides the Long Beach facility, aquariums in Baltimore, Dallas, Japan and Germany are trying to breed the weedies.
The trailblazer was Mr. Mom. A floating media darling whose pregnancy last June was chronicled by international media, he incubated about 80 eggs at the Aquarium of the Pacific. But Mr. Mom died in his fifth week of the usual six-week pregnancy, forcing the premature hatching of two dozen eggs, only 10 of which survived, and then just for a day or two.
Curators speculate that the creature might have succumbed to stress after he started to lose some eggs and was moved to a solo tank where other weedies and his leafy sea dragon brethren would not pester him. So this time, Big Daddy will stay put and remain in a mesh basket within his home tank, which is shared by his girlfriend and 22 other sea dragons.
Thus he’s not lonely but doesn’t have to fight for the hundreds of shrimp he consumes daily. Curators say he appears calm--no odd movement or sideways swimming--and drifts about vertically because of the eggs’ weight. His habitat is under tight control, with sometimes hourly adjustments in water temperature.
Big Daddy remains available for public viewing, as long as nobody uses a flash camera. The aquarium, which will mark its third anniversary next month amid financial struggles, has attempted to increase attendance by personalizing some of its 12,000 fish and other species native to the Pacific Ocean.
On Wednesday, signs heralding the rare pregnant male were not yet in place. But tour guides started spreading the word to some of the schoolchildren on field trips.
“A boy having babies,” said one incredulous first-grader, “is kind of cool.”
