Divers think they barely touch coral, then underwater observers tally the damage

Scuba tourism is often pitched as benefiting both reef conservation and coastal livelihoods, while giving visitors a firsthand view of coral ecosystems.

Yet studies indicate that the activity can also harm reefs, and many divers may not realize how much damage they are causing.

What's happening?

According to new research discussed in The Conversation, a team of scientists tracked 732 recreational scuba divers at reef destinations in Indonesia and the Philippines, comparing what divers believed they were doing underwater with what trained observers actually recorded.

The team found that divers made contact with the reef roughly every four minutes on average, and more than 40% of those incidents caused visible damage, including broken coral or sediment settling on living reef surfaces, The Conversation noted.

What divers thought they were doing often differed sharply from what observers saw. Participants estimated that they came into contact with the reef only about one-fifth as often as they actually did, despite believing they were better than average at avoiding both intentional and accidental contact.

The issue also appeared to be social. Reef contact by one diver seemed to make similar contact more likely among nearby divers. Encounters with charismatic marine animals such as sharks, turtles, and manta rays increased the odds of both accidental and intentional reef contact.

Why does it matter?

Tourism-related reef contact adds another source of strain to coral ecosystems already dealing with ocean warming, pollution, and acidification. That extra physical damage can make recovery even more difficult.

Healthy reefs help shield coastlines from storm surge, support fisheries, and sustain tourism jobs in communities that depend on ocean visitors. If reef-based ecotourism gradually degrades the reefs themselves, it can weaken an important economic lifeline for local families and businesses.

Diving is often framed as a way to build appreciation for the ocean, but this research suggests admiration alone does not always lead to low-impact behavior. The experiences that most inspire divers may also coincide with moments when reefs are especially vulnerable.

Protecting reefs is not only about large-scale science and policy. It also depends on the small, repeated choices people make underwater.

What's being done?

The researchers said the damage linked to diving can be reduced. They pointed to better buoyancy skills, clearer pre-dive briefings, and stronger guide leadership as ways to limit reef contact.

Dive operators can also lower the risk by keeping groups smaller and setting appropriate viewing distances when marine life is nearby. That is especially important because exciting wildlife encounters can make divers less aware of where their fins, hands, or gear are moving.

Equipment may also be part of the problem. The use of items such as underwater cameras, gloves, and muck sticks was associated with more frequent reef contact. Some dive destinations have already introduced rules limiting those items, even if those restrictions are not always popular.

One practical step is choosing operators with strong sustainability standards. Green Fins certification — an international program focused on responsible marine tourism — was linked to fewer intentional reef contacts, especially at stronger-performing dive centers. Divers can also help by seeking honest feedback, practicing buoyancy, and giving reefs and wildlife more space.

As the researchers wrote via The Conversation, "People may not change their behaviour if they do not realise they are part of the problem." They added: "The best way to enjoy marine life is with space and respect."

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