Seattle Aquarium unveils exhibit of coral grown in-house

After a little super glue, lots of clean water and many months to grow, a group of colorful critters is ready for the main stage.

The Seattle Aquarium recently unveiled its first large exhibit devoted to corals grown in its laboratory. The 2,500-gallon tank, located halfway through a meandering corridor showcasing tropical fish, invertebrates and plants, now is filled with nearly 20 different coral species mostly grown in-house.

"We've had corals and clams in smaller exhibits on public display, but this was just a great opportunity to really highlight what we've been doing with in-house propagation techniques," said Andy Sim, a Seattle Aquarium biologist.

Biologists will adjust parts of the exhibit for several more months, then allow the corals to grow and fill the tank.

The aquarium started remodeling its lab space two years ago to accommodate growing corals. New water storage and pipes, high-intensity lighting and shallow tank space were added.

Most corals are invertebrate organisms made up of multiple animals living together in colonies. One small coral fragment can include hundreds of individual creatures. Coral forms a calcium-based skeleton, and living tissue grows over the skeleton's supportive frame.

Corals live in nearly every saltwater environment around the world, including Washington's waters. Large, colorful coral reefs usually thrive in tropical waters such as the South Pacific and Indian oceans. In recent years some reefs have faced die-offs and massive destruction. Experts cite polluted, warmer water as the culprit.

"Coral has been around for a really long time, but it's not very adaptable," Sim said. "It survives well in very stable conditions."

The biggest concern now is the impact climate change could have on coral reefs, said Terrence Gosliner, senior curator of invertebrate zoology and geology at the California Academy of Sciences. As the ocean absorbs carbon dioxide and its water becomes more acidic, coral reef skeletons are vulnerable to breaking down, he said.

Still, coral fragments can be legally harvested in some places with proper permits. An international organization has formed to set standards for sustainable harvesting.

Most large- and medium-sized aquariums now grow some of their own coral for exhibits instead of taking from wild reefs, Sim said. Aquariums tend to specialize in the kinds of coral they raise, and it's common to trade species among facilities.

Locally, Seattle Aquarium and Point Defiance Zoo & Aquarium in Tacoma often trade corals grown in their labs. The Tacoma aquarium has had success growing hard, stony corals and can offer them to other facilities, said John Rupp, aquatic-animal curator for Point Defiance Zoo & Aquarium.

Biologists need only a tiny coral fragment — and plenty of time — to grow enough for an exhibit. With adequate light, temperature and water flow, corals can grow, plus propagate asexually or spawn with each other.

For this exhibit, Seattle Aquarium biologists started by super-gluing small coral fragments to stones and placing them in shallow tanks. When species grew large enough, biologists transferred the animals to the larger exhibit. The corals will continue to grow and propagate, filling the tank over time, Sim said.

"We place them in a way to plan for future growth," he said. "It still looks sparse right now, but we have to give animals room to grow."

The exhibit will look different in just six months, but probably won't be completely filled for several years. A small fragment can take six months or a year to reach baseball size, Sim said.

Seattle Aquarium also gets coral from aquaculture companies that grow and sell the animals for public aquariums and aquatic pet stores.

The aquarium also gets a small amount of wild coral from the U.S. Fish and Wildlife Service. The agency confiscates live corals that are brought into the country illegally, then contacts local aquariums to see if they have space to take them, said David Cripe, special-exhibits coordinator with Monterey Bay Aquarium in California.

Michelle Ma: 206-464-2303 or mma@seattletimes.com