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Published on: November 20, 2017
eRNA Reveals Real-Time Signals of Freshwater Fish Population Biomass and Total Abundance
J Beaulieu1,2, W B Morgado-Gamero2,3, D J Fraser2,4
1Département Des Sciences Biologiques, Université du Québec à Montréal, Montréal, Québec, Canada.
Molecular Ecology
|June 3, 2026
Summary
Environmental RNA (eRNA) shows strong potential for estimating fish biomass and abundance in aquatic ecosystems. This method offers higher resolution and fewer false positives compared to environmental DNA (eDNA) for effective ecosystem monitoring.
Area of Science:
- Ecology
- Molecular Biology
- Fisheries Science
Background:
- Accurate fish biomass and abundance data are vital for ecosystem management, but traditional methods face challenges due to increasing anthropogenic pressures.
- Environmental DNA (eDNA) offers cost-effective monitoring but suffers from high molecular stability, leading to potential false positives.
- Environmental RNA (eRNA), with its faster turnover rate, presents an opportunity for improved spatio-temporal resolution and reduced false positives in ecological assessments.
Purpose of the Study:
- To evaluate the efficacy of eRNA in predicting fish biomass and abundance in natural lake ecosystems.
- To compare the predictive capacity of eRNA markers against eDNA markers with varying turnover rates.
- To assess the impact of allometric scaling on eRNA-based biomass predictions.
Main Methods:
- Comparison of mitochondrial cytochrome b (cyt b) and nuclear ribosomal 18S markers using both eDNA and eRNA samples.
- Correlation analysis between marker concentrations and fish biomass data obtained from mark-recapture studies.
- Evaluation of eRNA marker performance with and without the integration of allometrically scaled fish mass.
Main Results:
- All tested markers (eDNA and eRNA) showed positive correlations with fish biomass.
- eRNA markers, particularly mRNA cyt b, demonstrated stronger relationships with fish biomass and abundance than eDNA markers.
- The mRNA cyt b marker effectively distinguished biomass and abundance differences between lakes, outperforming other markers.
- Allometric scaling did not enhance eRNA-based biomass predictions, unlike its potential effect on eDNA.
Conclusions:
- eRNA holds significant promise as a molecular tool for accurate estimation of fish population biomass and abundance in aquatic environments.
- The faster turnover rate of eRNA offers advantages over eDNA in terms of spatio-temporal resolution and reliability for ecological monitoring.
- mRNA cyt b emerges as a particularly effective marker for assessing fish biomass and abundance, resolving finer-scale ecological differences.
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