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06-08-2024

Marine protected areas lack critical fish habitats

A recent study has revealed that 62% of marine protected areas (MPAs) aimed at protecting migratory fish, especially rare species, fail to cover their essential habitats.

The research, conducted by a team from the French Biodiversity Agency, Institut Agro, and INRAE, highlights a significant gap in conservation efforts and underscores the need for better alignment between MPAs and the actual habitats of these fish.

The mismatch poses a significant challenge for conservation efforts, especially for threatened species such as shads and the critically endangered European eel, as listed by the IUCN.

What are marine protected areas?

MPAs are specific regions in oceans, seas, and large lakes where human activities are regulated to protect natural and cultural resources. These areas are established to conserve marine biodiversity, safeguard endangered species, and preserve vital ecosystems.

MPAs vary in their level of protection, from fully protected reserves where all extractive activities like fishing and mining are prohibited, to partially protected areas where certain activities are allowed under strict management.

The primary goal of MPAs is to create safe havens for marine life, allowing ecosystems to thrive without the pressures of human interference.

This helps maintain ecological balance, supports sustainable fisheries, and ensures the resilience of marine environments against threats such as climate change, pollution, and overfishing.

By protecting critical habitats, breeding grounds, and nursery areas, MPAs contribute to the overall health and sustainability of the world’s oceans, benefiting both marine life and human communities.

Challenge of protecting diadromous fish

Diadromous fish, migratory fish that transition between fresh and marine waters, face a unique set of challenges.

These species are subject to various threats, including agricultural runoff, habitat destruction, and climate change, which affect them throughout their complex life cycles.

Despite these pressures, the study shows that only 55% of the core habitats for these migratory fish fall within MPAs, and of those, only half have specific conservation measures in place.

For individual species, the situation is even more dire. The endangered Mediterranean twaite shad, for example, has less than 30% of its core habitat protected by MPAs.

For the European eel and European smelt, around 70% of their habitats are covered, but protection measures are scarce. Only 9% of MPAs have specific protections for the European eel, and none are in place for the European smelt.

New model for protecting migratory fish

The research team, based in France and collaborating across multiple institutions, has developed a new modeling approach to predict the core and unsuitable habitats for these migratory fish.

This “Combined Model for Accurate Prediction” aims to refine how conservation areas are designated by integrating more accurate data on species distribution and habitat needs.

Dr. Sophie Elliott, the study’s lead author, highlighted the urgency of the situation, noting the sharp decline in diadromous fish populations reported by the Living Planet Index. “Given these declines, it’s surprising that more isn’t being done to protect these species,” she stated.

Dr. Anthony Acou, a co-author of the study, emphasized the challenges posed by the lack of data on rare species, which often leads to spatial protective measures being implemented with little understanding of their actual distribution and habitat needs. He refers to this dilemma as “the rare species paradox.”

Enhanced protection of fish habitats

The study’s findings underscore the need for targeted conservation measures that are precisely aligned with the habitats of at-risk species.

“We hope that our ‘Combined Model for Accurate Prediction’ methodological framework can help improve accurate rare species distribution modelling for reliable biodiversity assessments, meaning conservation measures can be targeted in specific areas that protect rare and poorly detected species while also minimising conservation impacts on human activity,” said study co-author Dr. Laurent Beaulaton.

As the researchers look to expand their modeling approach to larger areas in the Northeast Atlantic, they emphasize the need for additional data to better characterize functional habitats such as migratory corridors, nursery areas, and refuges.

A call to action for migratory fish habitats

The study serves as a call to action for policymakers, conservationists, and researchers to reevaluate and enhance the effectiveness of marine protected areas.

By aligning conservation efforts more closely with the actual needs and habitats of rare and migratory fish species, there is hope for reversing the troubling declines in these important populations.

The study is published in the Journal of Applied Ecology.

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