Seeding seaweed to heal Waikiki’s reefs

[USA] Limu kala is a tough type of seaweed with “healing properties.” It is prized by Hawaiians for cultural and medicinal uses.

And while it used to be abundant along Oahu’s South Shore, it’s now scarce.

That’s why UH botanists have turned to everyday “tile” for help.

Tiny juvenile limu kala are being grown on little squares that will end up doting a section of reef in Waikiki.

“There are two-by-two tiles. They are made of limestone which is what the reefs are constructed of, and we can takes these tiles, cement them to the reef and the Sargassum can grow and reproduce and hopefully re-establish in Waikiki,” said UH researcher David Spafford.

It’s taken a lot of trial and error to learn that the seaweed is most fertile in winter, and that using makeshift surge tanks that mimic the movement of waves can actually speed up the growth of seaweed four times more than in calmer waters.

“It takes waves that would knock you off the rocks and it just loves it. The surge isn’t going to harm it. They love the surf so the more wave action the better,” said Spafford.

Surge-loving seaweed now unlocking its secrets under the patient work of researchers.

“We have learned a lot in the last three years: how it grows and how fast it grows, and how to get it grow faster and survive. So we hope in the next year or two to get them out on the reef and we will monitor to see what the results are,” said Sarah Vasconcellos, a PhD botany candidate.


Over the past several years, hundreds of volunteers have focused on removing the invasive Gorilla ogo from our waters.

The focus has been on the reefs in the marine preserve behind the Waikiki aquarium.

One of those volunteers says it’s gratifying to see those efforts have made a difference in reducing the invasive species.

“At first it feels like you see the whole community stacking it in tons, and you wonder, is it ever going to work? So it’s been fantastic to see the progress with that,” said Samantha Flounders, who has just graduated with a degree in Marine Biology.

“Right now is actually a prime time to take something in and hope they overgrow and out compete the invasive species if they start to come back up,” said Vasconcellos.

The real test of all this research will be out on the reef where those little tiles will be placed. That should happen later this fall or early next year.

The hope is to see limu kala regenerate, drawing more fish and encouraging diversity in the marine ecosystem and healing our unhappy reefs.

“We are working to provide the tools to innovate so we can help Waikiki turn a corner and show off the best rather than a degraded ecosystem,” said UH Botany professor Celia Smith.

After nearly 30 years of research in Hawaii waters, Smith is glad her focus is less on the invasive species and more about how to nurture native marine plants.

Little beds of limu kala are toughing it out for now and getting a helping hand from the hardware store and a few fish.

“We have 550 native reef plants, and limu kala is the only one we have cracked at this point to this stage. So we have huge uphill battles, or if you are an optimist, great opportunities to innovate and bring on line new species,” said Smith.

The story here is all about propagating, and preserving marine plants and nurturing a reef.

Scientists who believe the pilot project shows great promise say work is underway to expand it to Molokai.


View original article at: Seeding seaweed to heal Waikiki’s reefs




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