Abstract:

Background & Aims: Endangered aquatic species face greater survival challenges than their terrestrial counterparts under increasing pressures from global climate change and human activities in marine and freshwater ecosystems. Accurate data on population size, density, distribution, and dynamics are critical for effective conservation, yet traditional field surveys suffer from limitations such as high labor demands, subjective biases, and low efficiency due to the rarity of these species. Moreover, conventional methods often disturb both target organisms and their habitats. So it is an urgent need to explore technological improvements or replacements. 

Progress: Environmental DNA (eDNA) technology addresses these challenges by detecting species-specific DNA fragments in water samples, enabling non-invasive monitoring of presence, distribution, and abundance. In recent years, environmental DNA (eDNA) technology has gradually emerged as a prominent tool for monitoring and protecting endangered aquatic species. This paper overviews the eDNA applications for tracking single endangered aquatic species, including population distribution, abundance, biomass, and dynamic of life-history. It summarizes the complete technical workflow-from species-specific primer and probe design, laboratory simulation experiments, and mathematical model construction, to field sampling and laboratory analysis-highlighting each critical step. Furthermore, the review examines the principal factors influencing eDNA detection accuracy, including biological variables (e.g., biomass, body size, physiological status), environmental parameters (e.g., water temperature, pH, flow regime), and potential errors introduced during technical procedures, while objectively addressing current limitations in precise quantification and discrimination of living individuals. 

Prospect: The future development direction of eDNA technology’s integration with multiple technologies such as remote sensing and artificial intelligence to achieve standardized and intelligent monitoring was prospected, with the aim of providing new methodological support and theoretical frameworks for conserving these vulnerable or endangered species.

Key words: environmental DNA, endangered aquatic animals, population monitoring, technical process, influencing factors