Research chronicles improved conditions at Hanauma Bay during closure

2nd Annual Carrying Capacity Survey completed and published online

News Release from City and County of Honolulu, August 28, 2020

HANAUMA BAY – Of the many unforeseen circumstances presented by the COVID-19 pandemic, the reduced human presence at locations around our islands has presented a unique opportunity to better understand and manage our impacts on the natural environment.

Of those locations, the Hanauma Bay Nature Preserve is arguably the most prominent. During a regular year, the bay would host on average nearly 3,000 people every day (except during regular Tuesday closures). Since the March 18 closure in response to the pandemic, only researchers and staff have left foot prints on the shoreline of the nature preserve.

Instead of human footprints, researchers have noticed larger fish and the continued increase in monk seal activity within clearer ocean waters of the Nature Preserve.

From preliminary observations comparing water clarity during the pandemic closure to data from two years ago, average water clarity was 18% clearer (improved visibility of 2.0 meters, +/- 0.9 meters) than regular Tuesday closures and 42% clearer (improved visibility of 4.9 meters, +/- 1.0 meters) than days when the bay was open to the public.

Earlier data similar to this is included in the 2nd Annual Biological Carrying Capacity Survey for Hanauma Bay, which also provides information: comparing the impacts of coral bleaching events in 2015 and 2019, monitoring the biodiversity and characteristics of the bay’s marine life, and eventually determining acceptable limits of human disturbance with this unique ecosystem.

You can access the 2nd Annual Biological Carrying Capacity Survey by visiting the official Honolulu Department of Parks and Recreation Hanauma Bay website or by clicking here.

In addition to ongoing research of the human impacts on the nature preserve, maintenance and upkeep of the facilities has continued during the closure, including: planning for renovations of the sewage system, replacing invasive plants with native flora, and bathroom makeovers. 

A historically significant location for Native Hawaiians paddlers, and a favorite fishing location for some Hawaiian Royalty, Hanauma Bay was designated the state’s first Marine Life Conservation District in 1967.

Its popularity grew in the 1970’s and 1980’s when visitor attendance peaked at an estimated 10,000 people a day. A management plan implemented in 1990 helped to mitigate this human impact by: reducing visitation, improving facilities, banning the feeding of fish, and educating bay visitors. In 2019, average daily attendance was almost 3,000 people, with nearly 845,000 tourists and residents visiting the nature preserve that year.

In response to the COVID-19 pandemic, the nature preserve has been closed since March 18, 2020. Currently, there is no set public reopening date.

—PAU—