By Maria Elena De Matteo

This story is based on a transcribed interview with Professor Just T. Bayle-Sempere, marine ecologist and researcher at the University of Alicante.

Professor Just T. Bayle-Sempere has spent his career asking one deceptively simple question: “What happens when you protect the sea?” Over the past three decades, his research has taken him from the waters off Alicante to the Balearic Islands, gathering evidence on how Marine Protected Areas (MPAs) change ecosystems—and the lives of those who depend on them.

“There’s no doubt that MPAs bring benefits,” he says. “Fish populations recover. Tourism grows. Even fishermen—though at first sceptical—begin to notice improvements. But these things take time.”

‍

Tabarca: A Small Island, a Big Shift

One of Spain’s earliest MPAs, the Reserva Marina de Nueva Tabarca, is where Just has seen change unfold most vividly. Located off the coast of Alicante, Tabarca is a tiny island whose MPA designation triggered more than just ecological restoration.

“Before the reserve was created, the island didn’t even have basic services,” he recalls. “No running water, no electricity, no sanitation. But after the MPA came, local governments started investing.”

The improvements were both environmental and social. Tabarca’s marine life began to recover, drawing divers and eco-tourists. Infrastructure followed: waste systems, electricity, and tap water—all of which helped improve the quality of life for the small island population. For local fisherfolk, the return of fish stocks didn’t just stabilise catches; it restored a sense of long-term viability.

“It’s not just about fish,” Just says. “It’s about creating the conditions for people to stay, to work, to believe in a future tied to the sea.”

‍

‍

The Real Costs: Boats, Budgets, and Bureaucracy

Still, managing MPAs is no small feat. Surveillance is expensive—particularly the cost of maintaining boats and patrols. And while Spain has some strong MPA examples, many others exist only on paper.

“There are areas designated under the Habitats Directive with almost no management,” he says. “We call them paper parks. No real rules, no monitoring, no presence.”

Even where management plans exist, Just notes that they’re often too basic, focused on surveillance but not on long-term strategy, ecological goals, or stakeholder involvement. A good plan, he argues, is one that evolves, addresses conflict, and adapts to social and environmental shifts.

‍

When Protection Works

Beyond Tabarca, Just points to sites like the Medes Islands, Cabo de Palos, and the Parque Nacional Marítimo-Terrestre de Cabrera as strong examples. All have shown positive ecological outcomes: richer biodiversity, clearer waters, and healthier fisheries.

“In well-managed areas, you can measure the difference,” he says. “Not just in fish, but in people’s behaviour. Compliance goes up. Support grows. Even trust in institutions improves if they’re seen to do their job.”

Yet not all areas succeed equally. At Masia Blanca in southern Catalonia, for example, the MPA exists, but its ecological impact remains limited due to the simplicity of the seabed and the minimal management in place.

‍

People, Not Just Policy

For Just, one of the most overlooked dimensions is how MPAs affect social dynamics. While divers often welcome MPAs, seeing clearer water and more marine life, fishermen are more divided, especially in the short term.

“There are real conflicts,” he acknowledges. “Diving is allowed in many areas where fishing is not. That can be hard to accept when your livelihood is at stake.”

But even here, dialogue helps. Just cites one of his recent studies showing that regular, transparent communication with fishers increases their satisfaction and willingness to support marine protection.

“Sharing goals, listening to concerns—this matters. When fishers see that their voices are heard, that there’s a plan, they’re more likely to engage constructively.”

‍

The Takeaway

MPAs are not a magic bullet, Just insists. But when backed by real planning, sustained funding, and human dialogue, they become more than conservation tools. They become catalysts for positive change, making both nature and communities more resilient.

“We’ve seen it happen. But we need to move beyond the idea that putting a line on a map is enough. It’s the people, the relationships, and the day-to-day work that make protection real.”

‍