Are we loving Hawaiian coral reefs to death?

Author: Jill Ashey

Editor: Skylar Collins

Paper: Lin et al. (2023). Coral reefs and coastal tourism in Hawai‘i. Nature Sustainability. doi: 

Hawai‘i is an incredibly popular tourist destination, with tourism being the largest source of private capital for the Hawaiian economy. In 2019 alone, over 10 million visitors arrived and spent almost $18 billion dollars1. When visitors come to the Hawaiian islands, over 80% of them participate in some form of ocean activity, such as swimming, snorkeling, diving, and jet skiing, among others. Coral reefs specifically are a major tourist attraction. Over 50% of all US tourists snorkel or dive on reefs while in Hawai‘i2. It is estimated that coral reefs contribute over $800 million of tourist revenue each year3.

Like reefs worldwide, Hawaiian coral reefs are facing major threats from global and local stressors. In order to protect this valuable resource, tourism has been proposed as a means to protect coral reefs by generating funds for coral reef conservation and the sustainable use of marine resources4. However, tourism may be doing the corals more harm than good. A recent study from researchers at Princeton University and Arizona State University found that while live coral cover increases rates of overall visitation, visitation also contributes to the degradation of coral cover.

How did they do it?

The authors of the innovative 2023 study leveraged the power of social media, combined with aerial coral cover mapping, to describe how tourism affects coral cover. They used Instagram as a proxy for tourist visits to specific locations, reasoning that when visitors go to Hawaii coastal areas, they typically post pictures of their trip on Instagram. To gather data from Instagram posts, the authors ‘web-scraped’ for Instagram public posts from 2018-2021. Web-scraping is a technique used to extract large amounts of data from databases, typically implemented by specialized code. From each post identified by web-scraping, metadata on the location, time, caption, hashtag, and username was collected for analysis. Additionally, reef-related keywords (including “coral”, “reef”, “snorkel”, “scuba”, “underwater”, and “padi dive”) were employed to identify relevant posts. 

Aerial mapping coupled with artificial neural networks was utilized to quantify live coral cover at 2 meter to 16 meter resolution scale across the Hawaiian islands. This data, along with human activity, site accessibility and water quality data (retrieved from the Ocean Tipping Project and the Hawaii Statewide GIS Program), was also obtained for analysis. 

What did they find? 

Sites with high live coral cover and greater accessibility to tourists (i.e., close to roads or hotels) were visited most often, both in terms of overall visitation (visiting the beach/area around the reef) and on-reef visitation (visiting the reef itself). However, high rates of tourism at these popular sites led to suppressed live coral cover, resulting in reef degradation. On Oahu specifically, popular locations like Waikiki Beach and WaimeaBay have high levels of visitation rates and degraded coral cover (Figure 1). 

Corals are both directly and indirectly impacted by tourists through on-reef and overall visitations. When diving or snorkeling on reefs, tourists often come into direct contact with corals, causing harmful colony breakage to occur. Additionally, reef proximity to places with a high concentration of tourists can also be harmful given the elevated levels of pollution and increased infrastructure development that occurs. 

Figure 1: Relative coastal visitation rates across main Hawaiian islands.

Tips to safely interact with Hawaiian coral reefs

  • Do not touch, kick or disturb the corals! These actions may damage or kill corals, leading to further reef degradation. 
  • Wear reef-safe sunscreen! Certain chemicals in regular sunscreen can be harmful to corals. 
  • Support a tourist green fee in Hawaii! For every tourist to visit the Hawaiian islands, they would have to pay a $40 to $50 tourist green fee, which would go towards protecting Hawaii’s natural resources. Learn more about the proposed Hawaii green fee here: 


1. Fact Sheet: Benefits of Hawai‘i Tourism Economy (2019). Hawai‘i Tourism Authority.

2.Hawaii’s Local Action Strategy to Address Recreational Impacts to Reefs (2005). Department of Land and Natural Resources, Division of Aquatic Resources, and Hawai‘i Ecotourism Association.

3. Coral Reef Alliance.

4. Tourism in the 2023 Agenda (2015). United Nations World Tourism Organization.

Featured image: Andrea Sperling via Getty Images.

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