Oyster Pilot Project Launched on Maui to Improve Water QualityFebruary 1, 2020, 3:48 PM HST · Updated February 1, 3:50 PM Wendy Osher · 12 Comments
An innovative pilot project that uses oysters to improve water quality at Maui’s Māʻalaea Harbor was launched on Friday by the Maui Nui Marine Resource Council.
“Today we’re starting with 518 oysters–is the final count. We have the Pacific Oyster–which is the common species that’s with us today. It was born and raised in Hilo… at the Pacific Aquaculture and Coastal Resources Center,” said Amy Hodges, Programs Manager for the Maui Nui Marine Resource Council.
Oysters are used around the world to help improve water clarity and quality, allowing for sunlight penetration, which is important for corals and other animals.
According to project organizers, oysters have also been put to work in the Chesapeake Bay, where the US Army Corps of Engineers has been rebuilding traditional oyster reefs using shells from mollusks consumed in restaurants. In New York Harbor, an ambitious project called the Billion Oyster Project hopes to install enough oysters to totally filter the entire harbor every three days.
“Our goal is to use the oyster’s natural filter feeding abilities to make Māʻalaea Bay cleaner and healthier for fishing, swimming, paddling and surfing,” notes Hodges.
“We are hoping to improve the water quality here to help the coral and the fish here in the harbor and ultimately in the bay. And if everything goes well here, which we think it will, it’s an example of a project that can be expanded across Maui and already it’s happening on other islands,” said Hodges.
Project partners note that the variety used are not the pearl producing kind, and are not suited for consumption because of the impurities that they are filtering.
“It’s important that the public understand these oysters are not suited for eating,” says Hodges. “There’s too much pollution here to make it safe to consume them. You don’t want to get sick with diarrhea and vomiting due to eating oysters from polluted water. Instead, please get your oysters from places with clean water and leave these oysters to do their work of making Māʻalaea Bay better for fishing, surfing and ocean recreation for everyone.”
“We cannot eat these oysters and really the Pacific Oyster is a very good choice because it filters so much water. That’s one of the reasons it’s used for this in other places. It can filter up to 50 gallons of water a day for one oyster which is phenomenal,” said Rhiannon Chandler-‘Īao, Executive Director of Waterkeepers Hawaiian Islands.
“While they are filtering, they can suck in the sediment. And then they’re like, well I don’t really want to eat the sediment, so they produce a pseudo feces, like a little pellet that they expel, and so they remove the sediment from the water column and spit it out in this little pellet that falls to the floor,” said Hodges.
“Oysters are nature’s most efficient water filters; they eat by pumping large volumes of water through their bodies and in the process, they capture sediment and pollutants from the water column,” said Hodges.
“Hawai‘i’s nearshore ocean waters are not supposed to have too much phytoplankton, but fertilizers and wastewater nutrients such as nitrogen, phosphorous and potassium cause algae blooms,” said Hodges in an event announcement. “Oysters feed on microalgae, which ultimately makes the water clearer and better for corals.”
The oyster pilot project in Māʻalaea is supported by the County of Maui Mayor’s Office of Economic Development with additional support provided by Hawai‘i Tourism Authority’s Aloha ‘Āina Program.
The Maui oyster project is in partnership with Waterkeepers Hawaiian Islands, a neighbor island nonprofit which now has 10,000 oysters installed at four sites on O‘ahu–at Pearl Harbor, Kāne‘ohe Bay Marine Corps Base, and Ala Wai Harbor.
“This is an important step past water quality monitoring. I mean, we want to know what’s going on with the water, but we also want to do something about what’s happening in the water,” said Chandler-‘Īao.
Project parters say there are 90 water bodies in the state that are impaired. Māʻalaea was selected because of it’s unique challenges relating to wildfires and sediment.
“The challenges are tremendous because Māʻalaea is the driest part of the island, the windiest part fo the island and the most fire prone part of the island,” said Larry Stevens, Board Member with the Maui Nui Marine Resource Council. “And when the fires burn, the plants are torched, much of the soil becomes loose, so when the rains come, it all erodes into the ocean.”
While oysters are being used within the bay, a stormwater management plan is being developed at the 4,000-acre Pohakea watershed above the harbor to reduce sediment-laden runoff flowing into the ocean, and reduce fire risks by creating fire and fuel breaks on the mountainside.
“MNMRC commissioned the extensive
“The oysters will help with the problems that are here now, but let’s try and limit the problems from even starting, so that’s why we’re looking mauna as well,” said Hodges.
“If the pilot project goes well, in about a month we’ll know if these guys survive and can live, and then we’ll begin growing out the next batch of babies that can be added toward the end of the year,” she said.
To gather baseline data about current ocean water quality in Māʻalaea Bay, Maui Nui Marine Resource Council is conducting regular kayak-based ocean water monitoring throughout the bay, using an electronic monitoring probe that provides a stream of data in real-time as the kayak travels through the water. The probe was purchased as the result of a grant from Lush Cosmetics Charity Pot.
Staff will be pulling up the cages every two weeks to monitor the oysters and clean their cages.
***Supporting information courtesy Maui Nui Marine Resource Council.
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