Oysters to Help Improve Water Quality in Pearl Harbor

Photo courtesy of U.S. Navy.

A native species of oysters is making a comeback to help improve water quality in the Pearl Harbor estuary.

The effort is the first large-scale project to use native shellfish for harbor water quality improvements, and is modeled on previous research conducted by the University of Hawai‘i at Hilo with native Hawaiian Oyster species in Hilo Bay.

Historically, the Pearl Harbor area was known as “Wai Momi” or “pearl waters.” Native shellfish species were once abundant in the Pearl Harbor area which was once known as “Wai Momi” or “pearl waters.”

The project is a partnership effort between the U.S. Navy, O’ahu Waterkeepers and UH Hilo’s Pacific Aquaculture and Coastal Resources Center (PACRC).

“Our partnership with O‘ahu Waterkeepers on this oyster remediation project is a great example of Navy’s initiative of improving and taking care of our environment,” said Capt. Jeff Bernard, commanding officer of the Joint Base Pearl Harbor-Hickam.

The project is based on a successful feasibility study conducted by the Department of Land and Natural Resources, Division of Aquatic Resources, utilizing a nonnative species, Crassostrea gigas (known as the Pacific Oyster), as a tool to improve water clarity and quality within Pearl Harbor.

The Pacific Oyster survives and grows well in Pearl Harbor and it may continue to be used for bioremediation. The new project will focus on native shellfish species because of their cultural significance and to help replenish and restore a native marine ecosystem.

Two species of oysters native to Pearl Harbor will be used during the project: Dendostrea sandvicensis (Hawaiian Oyster) and Pinctada margaritifera (Black-lip Pearl Oyster).

“We are developing hatchery production methods for native bivalve species, in part because many local species have become rare and may possibly require protection,” said Dr. Maria Haws, director of PACRC. “For example, the Black-lip Pearl Oyster is already a protected species under state law.”

Native oysters filter between 20 and 45 gallons of water per day, depending on their size, removing harmful pollutants like sediment, bacteria, heavy metals, PCBs, oil, micro-plastics, sunscreen chemicals and nutrients from the water column. Oysters also remove carbon from the water and use it to build their shells, mitigating climate change effects in the marine environment.

“This project will further the Navy’s environmental stewardship activities in Pearl Harbor and hopefully lead to long-lasting positive effects on the harbor through sustained augmentation of oyster beds,” said Cory Campora, Navy’s natural resources manager.