Scientists use straws to protect infant corals from fish

Fri, Apr 12, 2024 page5

Scientists use straws to protect infant corals from fish
- AP, FORT LAUDERDALE, Florida
South Florida researchers trying to prevent predatory fish from devouring laboratory-grown coral are grasping at biodegradable straws in an effort to restore what some call the rainforest of the sea.
Scientists around the world have been working for years to address the decline of coral reef populations. Just last summer, reef rescue groups in South Florida and the Florida Keys were trying to save coral from rising ocean temperatures. Besides working to keep existing coral alive, researchers have also been growing new coral in labs and then placing them in the ocean.
However, protecting the underwater ecosystem that maintains upwards of 25 percent of all marine species is not easy. Even more challenging is making sure that coral grown in a laboratory and placed into the ocean does not become expensive fish food.

An image taken on July 26 last year and provided by WinCup shows a “Coral Fort,” made of biodegradable drinking straws that researchers are using to prevent laboratory-grown coral from becoming fish food, off the coast of Fort Lauderdale, Florida.

Photo: AP

Marine researcher Kyle Pisano said one problem is that predators like parrot fish attempt to bite and destroy the newly transplanted coral in areas like South Florida, leaving them with less than a 40 percent survival rate. With projects calling for thousands of coral to be planted over the next year and tens of thousands of coral to be planted over the next decade, the losses add up when coral pieces can cost more than US$100 each.
Pisano and his partner, Kirk Dotson, have developed the Coral Fort, claiming the small biodegradable cage that is made in part with drinking straws boosts the survival rate of transplanted coral to more than 90 percent.

“Parrot fish on the reef really, really enjoy biting a newly transplanted coral,” Pisano said. “They treat it kind of like popcorn.”
Fortunately, the fish eventually lose interest in the coral as it matures, but scientists need to protect the coral in the meantime. Stainless steel and PVC pipe barriers have been set up around transplanted coral in the past, but those barriers needed to be cleaned of algae growth and eventually removed.
Pisano had the idea of creating a protective barrier that would eventually dissolve, eliminating the need to maintain or remove it. He began conducting offshore experiments with biodegradable coral cages as part of a master’s degree program at Nova Southeastern University. He used a substance called, polyhydroxyalkanoate (PHA), a biopolymer derived from the fermentation of canola oil. PHA biodegrades in the ocean, leaving only water and carbon dioxide. His findings were published last year.
The coral cage consists of a limestone disc surrounded by eight vertical phade brand drinking straws, made by Atlanta-based WinCup Inc. The device does not have a top, because the juvenile coral needs sunlight and the parrot fish do not generally want to position themselves facing downward to eat, Pisano said.
Dotson, a retired aerospace engineer, met Pisano through his professor at Nova Southeastern, and the two formed Reef Fortify Inc to further develop and market the patent-pending Coral Fort. The first batch of cages were priced at US$12 each, but Pisano and Dotson believe that could change as production scales up.
Early prototypes of the cage made from phade’s standard drinking straws were able to protect the coral for about two months before dissolving in the ocean, but that was mot quite long enough to outlast the interest of parrot fish. When Pisano and Dotson reached out to phade for help, the company assured them that it could make virtually any custom shape from its biodegradable PHA material.
“But it’s turning out that the boba straws, straight out of the box, work just fine,” Dotson said.
Boba straws are wider and thicker than normal drinking straws. For Pisano and Dotson, that extra thickness means the straws last just long enough to protect the growing coral before harmlessly disappearing.
Reef Fortify is hoping to work with reef restoration projects all over the world. The Coral Forts are already being used by researchers at Nova Southeastern and the University of Miami, as well as Hawaii’s Division of Aquatic Resources.
Rich Karp, a coral researcher at the University of Miami, said they have been using the Coral Forts for about a month. He said that doing any work underwater takes a great deal of time and effort, so having a protective cage that dissolves when it is no longer needed basically cuts their work in half.
“Simply caging corals and then removing the cages later, that’s two times the amount of work, two times the amount of bottom time,” Karp said. “And it’s not really scalable.”
Experts say coral reefs are a significant part of the oceanic ecosystem. They occupy less than 1 percent of the ocean worldwide, but provide food and shelter to nearly 25 percent of sea life. Coral reefs also help to protect humans and their homes along the coastline from storm surges during hurricanes.
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