But by the 1950s, fishermen struggled to catch the fish they needed to feed their families. There were more fishing ships than ever, and they used new technologies to catch many fish at once. It seemed that there were not enough fish in the sea. When Wood grew into adulthood, he took over his family’s gardening business. Yet he remained an avid diver and spent lots of time in the water. What he saw disturbed him. In the 1970s, he’d see shoals of pollock and cod, as well as flatfish like turbot and plaice. But by the 1980s, the shoals grew rare — and so did deep-sea fish like rays and anglerfish. “You would only see one occasionally. And then you’d dive for a whole year and you wouldn’t see any at all,” he says. “It was a really drastic reduction in the amount of fish and the amount of marine life.”By the 1990s, even bottom-dwelling fish stocks collapsed. All that remained were shellfish like prawns and scallops, which thrived without any fishy predators. Around 70 percent of commercial fishermen and 95 percent of recreational angler fishermen had lost their jobs, says Wood. The people of the Isle of Arran suffered without work or a ready source of food from the sea.

Wood and his diver friends were distraught, but didn’t know what do to. As a gardener, Wood knew how to plant and care for nature on land — but in the sea, it’s a different sort of work. “The difference underwater is that if you leave things to just grow, they will replenish themselves,” he says. “The only thing you need to manage is man, not nature.”

Wood didn’t know it at the time, but he stopped seeing fish for a reason. And when he later learned what happened, the stubborn gardener would not let it stand.The next step was figuring out what changes they wanted to make. Wood did some research and found that, throughout the world, marine protected areas — regions protected from fishing or other human impacts to provide a safe sanctuary for sea life — worked to restore ecosystems and fisheries. By protecting some fish so they could reproduce, the benefits spilled out to a much larger area.