Mesophotic protected habitats as refugia for the most at-risk elasmobranch species

2025/07/24 by Franck Pichot, Stéphanie Manel, Laure Velez +13 · 1 voice · 1 citation
Environmental Science · #Environmental DNA in Biodiversity Studies #Ichthyology and Marine Biology #Marine Ecology and Invasive Species

paper · doi:10.1016/j.biocon.2025.111371

openalex publication_date 2025/07/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/22

Abstract

Coastal areas experience among the highest cumulated human pressures across the world's oceans with severe consequences on some fish populations which become scarce and at risk of local extirpation. Marine protected areas (MPAs) are essential for conserving these threatened populations, but they often cover only the most superficial waters and are not three-dimensionally extensive enough, leaving most mobile species with a large home range like elasmobranchs vulnerable to human pressures. Here we explored the role of mesophotic and deep-water habitats as refuges for elasmobranchs and the most at-risk species in the Parc Naturel Marin du Cap Corse et de l'Agriate, a large MPA in the Mediterranean Sea. Using the metabarcoding of 200 environmental DNA samples of seawater filtered between 1 and 835 m depth we revealed that fish species diversity was the highest in the mesophotic habitat (30-149 m). We also found the highest number of endangered species, including Evolutionary Distinct and Globally Endangered (EDGE) species such as Rostroraja alba and Squatina squatina , in this key habitat. Species composition varied significantly with depth, revealing a stratification linked to human pressure and environmental conditions. Protecting both mesophotic and deeper habitats (below 150 m) thus appears crucial to preserving biodiversity, species with unique functional roles but also those with unique phylogenetic diversity, in order to ensure ecosystem resilience in the face of climate change and overexploitation. The full protection of deep-water refuges within the western Mediterranean basin is essential to ensure the preservation of the most at-risk species, with the possibility of rewilding by connectivity other depleted adjacents habitats.

Citations

• Using eDNA to develop a national citizen science-based monitoring programme for the great crested newt (Triturus cristatus)
• Area-based conservation in the twenty-first century
• Rarity mediates species‐specific responses of tropical reef fishes to protection
• Ecological erosion and expanding extinction risk of sharks and rays
• Are Environmental DNA Methods Ready for Aquatic Invasive Species Management?
• Marine defaunation: Animal loss in the global ocean
• Extinction risk and conservation of the world's sharks and rays
• Phylogenetic diversity and nature conservation: where are we?
• Assessing spillover from marine protected areas and its drivers: A meta‐analytical approach
• Three‐dimensional conservation planning of fish biodiversity metrics to achieve the deep‐sea 30×30 conservation target

Cited by

• Exploring elasmobranch biodiversity in the western Mediterranean and Alboran Sea through eDNA-Based monitoring

Discussions

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