Smarter Marine Protection: Why Where We Protect Matters More Than How Much

Redacción HC
24/07/2024

With the world rallying behind the “30x30” goal—to protect 30% of the ocean by 2030—governments are racing to designate new Marine Protected Areas (MPAs). But are we drawing the lines in the right places?

A groundbreaking new study published in Proceedings of the National Academy of Sciences (PNAS) challenges assumptions about the effectiveness of marine conservation. Led by researchers from the University of California Santa Barbara, the World Bank, and other institutions, the study reveals that not all MPAs deliver the same environmental payoff, and location is far more important than coverage.

Using machine learning and global satellite fishing data, the researchers simulated how fishing fleets would respond to different MPA expansion scenarios. The findings have profound implications for ocean policy and sustainable fisheries management.

The Core Question: Does Expanding MPAs Actually Reduce Fishing?

The concept of MPAs is simple: restrict fishing in key ocean zones to allow ecosystems to recover. But critics have long feared that this simply pushes fishing effort elsewhere—a phenomenon known as “fishing the line.”

This study asks a sharper question:

How does global fishing activity shift when new MPAs are created—does it relocate, or does it actually decrease overall?

By modeling fishing behavior under a variety of expansion strategies (from 3% to 30% of ocean coverage), the researchers found that MPAs can reduce fishing effort significantly—if they're placed strategically.

How the Study Worked: Machine Learning Meets the Ocean

The research team trained a machine learning algorithm using:

• Satellite-based AIS data from Global Fishing Watch
• Current MPA boundaries
• Environmental and economic variables
• Political and geographic indicators

The model predicted how fishing effort (measured in total hours) would redistribute under six expansion scenarios. Crucially, it compared these with a “business-as-usual” scenario to isolate the real effect of MPAs.

The study focused on industrial fleets (vessels ≥24 m), due to AIS limitations, and did not include small-scale or artisanal fishing data.

Key Findings: Strategic MPAs Reduce Fishing Globally

1. Fishing Inside MPAs Drops Sharply

Three years after MPA implementation, fishing activity inside protected zones declined by up to 87%. This is strong evidence that MPAs are being respected—even by industrial fleets.

We expected some reduction, but seeing up to 87% was compelling, the authors note.

2. No Significant Displacement Effect

Contrary to fears of a spillover, fishing also declined outside MPAs, indicating an overall decrease in effort, not just a redistribution. This suggests MPAs can reduce ecological pressure across wider regions.

3. Location Matters More Than Size

The most effective MPAs were those placed in heavily fished areas. These zones reduced global fishing effort by up to 55%. In contrast, expanding MPAs in lightly fished waters led to only ~6% reduction.

Protecting empty ocean is like placing a traffic ban in a quiet cul-de-sac—little effect, one co-author explained.

4. Design Strategy Trumps Coverage Target

Hitting the 30% coverage goal alone isn't enough. The study argues that smart, data-informed placement is the real key to marine conservation success.

Practical Implications: Toward Smarter Ocean Policy

This research isn’t just academic—it offers actionable guidance for governments, NGOs, and ocean planners.

1. Target High-Pressure Zones First

MPAs should prioritize regions where fishing is intense. This maximizes conservation return and reduces ecological pressure more effectively than random placement.

2. Measure What Matters

Effort reduction is a good proxy, but future studies must also track catches, revenue, biodiversity outcomes, and social impacts—especially on small-scale fishers.

3. Integrate MPAs with Broader Management Tools

MPAs work best when combined with other tools like quota systems, seasonal closures, and community co-management.

4. Include Small-Scale Fisheries in the Picture

This study focused on industrial fleets, but many vulnerable coastal ecosystems are exploited by artisanal or subsistence fishers, particularly in Latin America, Africa, and Southeast Asia. These groups must be included in future models and policies.

Latin America’s Opportunity: Data-Driven Conservation

Regions like the Gulf of California, the Peruvian coast, and Brazil’s southeast corridor are rich in biodiversity and face intense fishing pressure. Smart MPA design could dramatically improve marine health without devastating livelihoods.

In Latin America, combining satellite data with local knowledge could revolutionize coastal protection, notes marine economist Jennifer Raynor.

Local governments, supported by international cooperation, have the chance to pioneer adaptive, equitable, and impactful conservation policies.

The Bigger Picture: Conservation That Works

This study marks a turning point in global marine conservation science. By applying predictive modeling to real-world fishing behavior, it offers empirical evidence that well-placed MPAs work—and poorly placed ones waste resources.

As nations strive to meet 30x30 targets, this research is a call for strategic thinking over symbolic gestures. Ocean protection is not just about how much—we must ask where and why.

Topics of interest

Biodiversity