Key Points from the Research on Angel Sharks Detection Using eDNA

Study Focus

  • Development of eDNA assay for detecting Squatina spp. (Critically Endangered angel sharks) in the Mediterranean Sea.

Research Objectives

  • To create a probe-based quantitative PCR (qPCR) assay.

  • To evaluate the distribution and presence of angel sharks through non-invasive methods.

Methodology Overview

  • Species Targeted:

    • Squatina squatina (angelshark)

    • Squatina aculeata (sawback angelshark)

    • Squatina oculata (smoothback angelshark)

  • Assay Specifications:

    • Targets a 173-bp barcode in the mitochondrial cytochrome c oxidase I (COI) gene.

    • Verification through in silico, in vitro, and eDNA samples (30 L of seawater).

Findings

  • Detection Results:

    • S. squatina detected in 7 out of 76 eDNA samples across Corsica.

    • Discovery of S. squatina extends its known range along the north-west Corsican coast.

  • Sampling Design:

    • Filtration of seawater conducted close to the substrate to optimize eDNA collection from benthic species.

  • eDNA Concentrations:

    • Varied concentrations reported, with notable findings at transects near marine protected areas.

Conservation Implications

  • Results can guide conservation strategies and public awareness efforts.

  • Future applications of the qPCR assay could aid in monitoring other threatened species.

Recommendations for Further Research

  • Validate the assay for S. aculeata and S. oculata in the field.

  • Investigate spatial and temporal patterns of angel shark presence using refined sampling protocols.