For the return trip, the Mariposa picked up the Shedd staffers and their prized collection, including a pair of lungfish, on May 6, then headed to Honolulu, where two other Shedd collectors were waiting with 13 more containers of triggerfish, puffers, hawkfish and other Hawaiian reef specimens. On May 23, the Mariposa docked in Los Angeles, where Shedd’s custom-outfitted railroad car, the Nautilus, was waiting at the wharf to be loaded. The crew and collection arrived in Chicago with a few days to spare before A Century of Progress opened.
The lungfish were the first of their kind on exhibit in the United States. While the aquarium never attracted the huge overflow crowds that Chute had hoped for, 4.58 million people did visit during the exposition’s two-year run and presumably were wowed by these large, unusual-looking fish from Down Under.
Australian lungfish are native to the Mary and Burnett Rivers in Queensland, in northeastern Australia. They are among the few fishes that can breathe air. This species has a single primitive lung as well as gills, allowing it to survive seasonal fluctuations in the level and quality of its shallow-water habitats by noisily gulping air at the surface every 30 to 60 minutes. Undoubtedly this was an advantage for the pair during their 3-week journey to Chicago.
They bred once—an extremely rare event in an aquarium—but a fungal growth destroyed the eggs. Granddad’s mate lived until 1980.
In 1994, Granddad was joined by five younger lungfish, a gift to Shedd from the University of Queensland and Australia’s Sea World park. Because of this species’ small population, severely restricted range and the degradation of its breeding habitat, it is listed as threatened in Australia, and the government rarely allows specimens out of the country.
The relative youngsters, estimated to be between 8 and 10 years old at the time of their arrival, were donated to the aquarium to establish a breeding program in the United States. In contrast to Granddad’s lengthy sea-and-rail journey, these fish, chaperoned by a biologist, traveled by jet from Brisbane to Chicago in a mere 24 hours.
Not a lot is known about lungfish reproductive biology. In fact, no one knew the gender of the new lungfish in 1994 because at that time, short of observing mating behavior, it required a surgical procedure to distinguish the sexes—not something casually undertaken with such rare animals. With the advent of portable ultrasound equipment, sonograms incorporated into the fishes’ regular physicals have confirmed that Granddad is a male while the younger group includes two males and two females. (A third male died in 1999.)
As yet the fish have not bred. Shedd researchers have tried replicating the subtle seasonal changes in water temperature and pH that trigger the hormonal boost that can put this species in a spawning mood in the wild. They are also studying additional habitat requirements. Even in the wild, however, Australian lungfish have been called “complacent” breeders. But with this species’ reputation for longevity, there appears to be time.
—Karen Furnweger, web editor