Columbus Zoo learns to breed saltwater fish to reduce use of wild ones

Alissa Widman Neese The Columbus Dispatch @AlissaWidman

It didn't take expensive, specialized equipment to raise a microscopic egg to develop into the first fish bred in captivity at the Columbus Zoo and Aquarium.

It mostly took patience — and a lot of plastic snack containers.

The elegant blue angelfish spent the first few weeks of its life in a repurposed pretzel jar full of saltwater before moving to the tide pool next to Discovery Reef. The 100,000-gallon aquarium is part of an international breeding effort aimed at reducing the number of fish collected from the ocean for private hobbyists and public zoos and aquariums.

Rising Tide Conservation, a New York-based nonprofit, is collaborating with 10 zoos and aquariums; six research facilities; the Association of Zoos and Aquariums, another nonprofit group; and SeaWorld to develop successful fish-raising techniques and share that knowledge with the world.

"It felt great," Columbus Zoo senior aquarist Ramon Villaverde said of the 2012 success with the angelfish, a hybrid of a few pomacanthus species.

But the breakthrough wasn't his end goal.

"I checked it off my bucket list, then looked toward what's next," he said.

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Villaverde has since upgraded his makeshift fish nursery.

After participating in a workshop funded by a grant from the Institute of Museum and Library Services, he received equipment that is a major improvement from the snack containers: two industry-standard tubs with specialized filters for raising the fish eggs collected from Discovery Reef.

Villaverde now has raised seven fish species from eggs. In addition to the angelfish, they are two types of clownfish, two types of cardinal fish, French grunts and lyretail anthias, often called "sea goldies" because of their vivid coloration.

The flame cardinal fish are believed to be the world's first bred in captivity.

Much of the progress still depends on the handmade plastic contraptions that led to Villaverde's early success with the angelfish.

The challenge of raising saltwater fish in captivity usually isn't getting them to spawn — when a female fish releases hundreds of eggs into a water column and they're fertilized by a male fish's sperm. Rather, it's what happens after a pair is finished mating.

The fertilized eggs are usually sucked up by the aquarium's filtration system, which removes waste from the water, or they're gobbled up by larger fish.

That's why the zoo's first baby angelfish stayed in a jar with no filter.

Villaverde created an egg collector using plastic totes, pipes, foam and mesh screen that floats on the water's surface after the zoo closes, because most fish typically spawn at night. A tube that's pumped with air ensures that the water keeps flowing, while eggs are left caught in the mesh.

Once trapped, the eggs are transferred to a behind-the-scenes area to begin growing.

It's a difficult process in the wild, where less than 2 percent of baby fish survive, typically due to predators, stress or lack of food.

In captivity, it's even more challenging.

Villaverde still keeps dozens of plastic snack containers, water-cooler jugs and 2-liter soda bottles, which he now uses to culture the various types of algae consumed by young copepods, the microscopic crustaceans the young fish eat as they grow from fragile, tiny larvae into adults.

Vats of brown, maroon and lime-green fluid bubble in a tiny behind-the-scenes area of Discovery Reef, resembling a strange science experiment or a recycled home brewery. The area is filled with aquariums and 5-gallon buckets.

Keeping the algae in pristine condition and figuring out what's needed to ensure that a fish survives to adulthood is an experiment all its own, Villaverde said. Several variables affect each species differently, including their complicated diets and the water's temperature, flow and quality.

"I try to think like a fish," Villaverde joked.

Once the captive-bred fish are large enough, many of them are returned to Discovery Reef or other exhibits at the zoo. The French grunts, for example, were bred specifically to stock the zoo's Manatee Coast. That kept the zoo from having to buy fish that have been removed from the wild, and paying to transport them.

Other fish bred at the Columbus Zoo are shared with other members of the Association of Zoos and Aquariums, a consortium of more than 230 accredited institutions in the United States and abroad.

The association encourages fish breeding if it benefits the environment or supports a conservation program, or if the species being considered for breeding is difficult to obtain from the wild, according to a 2016 white paper on the topic.

But the group also recognizes the potential positives of collecting fish from the ocean at sustainable, approved locations. That includes the genetic diversity it provides fish in exhibits, and the economic benefits and cultural significance it yields for the coastal communities that collect the fish.

Many aquarium hobbyists who privately breed fish also prioritize maintaining that balance and sustainability, said hobbyist Tal Sweet, co-founder of the Marine Breeding Initiative in Michigan.

Sweet said that in recent years he's noticing more hobbyists sharing information and collaborating on projects with public zoos and aquariums.

Rising Tide Conversation was founded in 2009 with that spirit of collaboration, spokeswoman Huntley Penniman said. The group unites zoos and aquariums that have plenty of egg-laying fish and tank space with researchers who can study and, ideally, improve their fish-raising techniques, she said.

The Columbus Zoo started its work with Rising Tide simply by collecting eggs.

Now Villaverde hopes his local breeding efforts can make a difference throughout the industry and ensure that wild fish populations thrive.

"People thought it was crazy, but I raised an angelfish in a pretzel jar," Villaverde said.

"It may be cheaper to buy some fish wild-caught now, but if we can figure out their ideal needs, it might be more valuable for zoos to raise them up ourselves someday."

awidmanneese@dispatch.com

@AlissaWidman

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