Hanauma Bay Nature Preserve, a popular snorkeling destination that attracts nearly a million annual visitors, underwent a remarkable and rapid recovery when tourism ceased during the 2020 COVID-19 pandemic.
Hanauma Bay Nature Preserve, a popular snorkeling destination that attracts nearly a million annual visitors, underwent a remarkable and rapid recovery when tourism ceased during the 2020 COVID-19 pandemic. A study from the University of Hawaiʻi at Mānoa Hawaiʻi Institute of Marine Biology (HIMB), published in npj Ocean Sustainability, found that this period of human absence led to clearer water, increased sightings of endangered Hawaiian monk seals, and more active fish populations.
“We took advantage of a unique ‘natural experiment’ created by the COVID-19 pandemic,” said Aviv Suan, project manager in HIMB’s Elizabeth Madin Lab, which leverages cutting-edge technology to research human impacts on marine ecosystems. “Hanauma Bay is normally a heavily visited site, but was completely closed to the public for seven months. We collected data on water quality, monk seal sightings, fish abundance, and fish behavior before, during, and after the closure. This allowed us to directly compare how the reef responded to different levels of human activity.”
By measuring the physical and biological health of the ecosystem, the research team found that when human visitors were absent, the reef in Hanauma Bay quickly returned to more natural levels. Fish densities changed, and vital herbivores such as parrotfish became more active in grazing algae.
Read more at: University of Hawaii
Photo credit: Fabien Vivier, Hawaiʻi Institute of Marine Biology Marine Mammal Research Program
