Unraveling the Drifting Larval Fish Community in a Large Spawning Ground in the Middle Pearl River Using DNA Barcoding

Abstract

Resolving the species composition of a larval pool in a spawning ground can provide novel insights into regional fish stocks and can support the development of effective monitoring and conservation policies. However, it is challenging to identify fish larvae to species due to their high diversity and dramatic phenotypic changes over development. In this study, we collected fish larvae in the Dongta spawning ground (Guiping City, Guangxi Province, China) in the middle reaches of the Pearl River between May and August 2018. We used a DNA barcoding approach to determine the species composition of the larval pool. A total of 905 larvae were chosen for molecular identification, of which 750 yielded high-quality barcoding sequences. Of these, 597 (≈79.6%), 151 (≈20.1%)/and 2 (≈0.3%) were assigned to 28 species, 8 genera, and 1 subfamily using the Barcode of Life Data System and GenBank nucleotide databases, respectively. Among the 28 identified species, 21 were cyprinids. Two species (Mugilogobius myxodermus and Pseudolaubuca engraulis) that were present only infrequently in previous adult surveys were abundant in the larval pool. Six invasive species were identified in the larval pool, implying that these species had successfully colonized the studied river section. Several migratory species common in the lower Pearl River were rare or absent in the investigated region, suggesting that dam construction in the Pearl River has had adverse effects on these migratory species. In summary, our study confirmed the applicability of DNA barcoding to studies of fish larval ecology and provided important reference data for fishery management and conservation in the Pearl River.

Attraction and passage efficiency for salmonids and non‐salmonids based on fishway: A meta‐analysis approach

“…There are many examples suggesting that the decline or obstruction of their migration routes caused by dams, culverts, or other anthropogenic activities, can impact freshwater biodiversity by directly decreasing the migratory fish populations (Antonio et al, 2007; Bao et al, 2019; Benitez et al, 2022; Frissell, 1993; Hatry et al, 2016; Pasha et al, 2015; Silva et al, 2018; Tan et al, 2022). For example, Chen et al (2022) found various economic migratory species (e.g., Ctenopharyngodon idella , Hypophthalmichthys nobilis , and Mylopharyngodon piceus ) which were historically common in the Pearl River have been rarely identified in the recent survey due to the long‐term obstruction of the Changzhou Dam. Consequently, dam removal (Silva et al, 2018; Whittum et al, 2023) and installation of fish passage facilities (i.e., fishways) (Clay, 1995; Ovidio et al, 2020) have been increasingly considered in an attempt to restore river connectivity worldwide.…”