Quantitative assessment of fish larvae community composition in spawning areas using metabarcoding of bulk samples

Area of Science:

• Marine biology
• Molecular ecology
• Fisheries science

Background:

• Accurate fish larvae identification is crucial for fisheries management but challenging due to larval morphology.
• Metabarcoding offers rapid, cost-effective monitoring but its quantitative accuracy is debated.

Purpose of the Study:

• To compare DNA metabarcoding with traditional morphological identification for fish larvae.
• To evaluate the taxonomic precision and reliability of abundance estimates using metabarcoding.
• To assess the suitability of metabarcoding for fisheries management and environmental impact assessments.

Main Methods:

• Compared DNA metabarcoding (12S gene) with morphological identification.
• Analyzed 332 fish larvae from the Irish and Celtic seas using standardized tissue amounts.
• Utilized multinet hauls at 14 offshore sites (0-50m depth).

Main Results:

• Metabarcoding showed a positive correlation with morphological assessment for relative family abundance (R S =0.81, P=0.007) and diversity (R S =0.90, P=0.002).
• Taxon richness and spatial community composition patterns were similar between both methods.
• DNA metabarcoding reliably estimated fish larvae abundance and community structure.

Conclusions:

• DNA metabarcoding of bulk tissue samples is a feasible and efficient alternative to morphological methods.
• This technique can be applied to monitor changes in fish larvae abundance and community composition in aquatic habitats.
• Metabarcoding provides a faster approach for ecological assessments and fisheries management.