Assessing the impact of the threatened crucian carp (Carassius carassius) on pond invertebrate diversity - a comparison of conventional and molecular tools

Invertebrate diversity was assessed in ponds (N = 18) with and without the crucian carp (Carassius carassius) in Norfolk and East Yorkshire using sweep-netting and microscopy, bulk tissue DNA metabarcoding, and environmental DNA (eDNA) metabarcoding. This project contains the raw sequence reads generated by High-Throughput Sequencing for the bulk tissue DNA and eDNA samples. Netted samples were size-sorted to create bulk tissue samples for DNA extraction. Water samples (5 x 2L) were collected from each pond and eDNA isolated from these. Bulk tissue samples were sequenced separately to eDNA samples to minimise cross-contamination. The impact of crucian carp stocking on alpha and beta diversity of ponds was assessed at species-level and family-level using sweep-netting and microscopy, bulk tissue DNA metabarcoding, and eDNA metabarcoding independently as well as combined. The methods were then compared for freshwater invertebrate assessment. Results will guide pond management in relation to conserving the crucian carp alongside other biodiversity, and freshwater invertebrate assessment using molecular tools.