Heedless divers speared tons of the most desirable game fish. A few divers might have caused little noticeable disruption, but safer, less expensive equipment and more leisure time helped popularize scuba diving. The five most crowded reefs attract 3,000 people on an average day and double that on warm weekends. Buoys can be lifesavers for coral by discouraging anchoring directly on the reefs, once the cause of massive destruction. Their boats pollute the water and everything in it with petroleum products and sewage.
Incompetent operators crash into the reefs.
They litter the sea with plastic foam cups, aluminum cans, glass, plastic bags, bottles, and miles of tangled fishing line. This debris does not go away - it is, for all practical purposes, indestructible. Thousands of swimmers routinely bump, scrape, and step on coral. To a tired swimmer, standing on coral may seem as harmless as resting on a rock. But the slightest contact by a foot, boat shoe, dive tank, or swim fin can weaken a section of living reef.