November 2011 – A group of people, standing above the Tennessee Aquarium’s Gulf of Mexico exhibit, watch aquarists below performing a saltwater rodeo. The last puffers, tangs and moray eels are rounded up and gently hoisted out of the nearly empty tank. They are being shared with other Aquariums wanting to add some dynamic animals to their exhibits. This is the beginning of something new. Something completely unlike the Aquarium’s other exhibits. Call it “Extreme Makeover – Aquarium Edition.”
Just like the popular television program, demolition begins once the residents move out. In this case, workers moved in with jackhammers almost before the last drops of water were drained from the tank. The décor replicating the mangrove forest and pelagic portions of the Gulf of Mexico were chiseled out. “We removed 87 tons of concrete from this exhibit,” said Rodney Fuller, the Aquarium’s facility and safety manager. “This was a big project and involved taking the tank down to its original concrete shell.”
While the pace was swift, the game plan had been in place for more than a year to make River Giants unique among Aquarium displays. “This is a pretty big departure from all of our other exhibits,” said Jackson Andrews, director of husbandry and operations. “Rather than showcasing animals from one ecosystem, River Giants is a collection of some of the world’s largest freshwater species. We’re able to tell the story of how these mega-fish are indicators of water quality and environmental health. Unfortunately, their future is uncertain.”
These fish are the Goliaths of freshwater. “Our Australian whiprays are already quite impressive with disc widths of more than three feet,” said Thom Demas, the Aquarium’s curator of fishes. “And they should grow larger on exhibit.” From Australia, the whiprays were flown to Los Angeles and then to Atlanta. Aquarists transported the rays by truck to Chattanooga. They have caused some wide-eyed stares in River Giants. “Many people are surprised when they see these guys. They have no idea freshwater rays get so big,” said Demas.
A batch of barramundi was trucked in from a Massachusetts fish farm where they’re raised for market as a sustainable seafood option. Barramundi are native to rivers from the Indo-West Pacific all the way down to northern Australia. These powerful looking fish are also true river giants, growing to more than six feet in length. Their silver colored backs slope downward to meet a face resembling a huge largemouth bass. This species lives most of its life in freshwater, but migrates to saltwater estuaries to spawn. “These fish are born male, but later in life many become female,” said Demas. “This gender change increases the successful reproduction and long-term survival for this species.”
Giant pangasius catfish are joined by Australian marbled eels, a beefy blue catfish weighing more than 100 pounds, prehistoric-looking arapaima and a group of alligator gar. A pair of wallagos, weird-looking catfish that seem like a mashup of knife-fish, eel and bullhead, capture a lot of attention. “They are one of my favorite fish because they’re so odd,” said Demas. “Our wallagos should grow rapidly on exhibit and may eventually reach lengths of more than seven feet.”
Tennessee Aquarium guests will discover how some river giants start out really small and later create some big problems. Redtail catfish, like those in the new exhibit, are native to the Amazon and Orinoco River basins in South America. Commonly sold in pet shops, redtail catfish look cute at first. “They have voracious appetites and grow quickly,” said Demas. “Pretty soon the new owner has a fish that outgrows a 55 gallon tank, not realizing these fish can reach overall lengths of more than four feet.” Unfortunately, in some locations these fish are illegally dumped into the nearest stream after becoming too large to handle. If conditions are favorable, these introduced catfish can wreak havoc on local ecosystems.
But far more of these mega-fish are in trouble rather than causing trouble. Once common in many of the great river systems of the world, these species are rapidly declining in the wild.
National Geographic explorer Dr. Zeb Hogan has documented 20 freshwater giants from around the world for his popular National Geographic Channel television series Monster Fish. In the Mekong River, Hogan documented a catfish that weighed nearly 650 pounds. While this individual might be the world’s largest freshwater fish, the Mekong catfish as a species is rapidly disappearing. “This species was listed as critically endangered in 2003,” said Hogan. “All of the countries of the lower Mekong have instituted regulations to closely monitor this species. Others are working on further conservation efforts to keep the Mekong catfish from going extinct.”
But for another freshwater giant, it may already be too late. Hogan went searching for the Chinese paddlefish in 2007. Sadly, his team documented what others suspected – that this species may be gone forever. “I worked with the scientist who had been searching the Yangtze River for these fish for decades, but our team never actually saw one,” said Hogan. “My understanding is the last Chinese paddlefish was seen in early 2007.”
A seven-foot lake sturgeon will be among the river giants in the new exhibit. It represents hope for the other freshwater species on the brink. Today anglers are reporting these prehistoric-looking fish along virtually the entire length of the Tennessee River. Hogan points to the work of the Tennessee Aquarium Conservation Institute and partners as a model for other giants that are vanishing. Making a connection by watching Monster Fish or seeing some of these river giants first-hand is an important step toward helping other big species. “We need to increase awareness to make sure everyone knows what’s happening in the wild,” said Hogan. “Without that knowledge, there’s no support to try and better protect these species.”
Collaborating with National Geographic on this new exhibit extends the freshwater conservation focus that has been the Tennessee Aquarium’s hallmark since opening in 1992. The National Geographic Society’s global freshwater initiative aims to inspire and empower individuals to preserve the extraordinary diversity of freshwater.
River Giants is yet another example of how Aquarium guests can have fun tapping into their fascination with some of the world’s most interesting fish. “We have a lot of amazing animals in both Aquarium buildings,” said Demas. “And I think this new collection of fish is a great way to celebrate the Aquarium’s freshwater roots on the Tennessee River.”
Guest Blogger: Thom Benson is the Communications Manager at the Tennessee Aquarium