Assessment of fishery resources using environmental DNA: Small yellow croaker (Larimichthys polyactis) in East China Sea

With the increase in fishing intensity and the intensification of marine pollution, the fishery resources in the Zhoushan Sea are seriously degraded, and the difficulty of censusing fish diversity hampers effective management in marine fishes. Environmental DNA metabarcoding and bottom trawl methods were used to determine the ability of the methods to distinguish fish assemblages in the Zhoushan Sea. The species composition and diversity of the Zhoushan Sea were assessed via high-throughput sequencing analysis of eDNA coupled with bottom trawl fishery survey data, after which the two methods were compared. eDNA screening identified 38.2% more fish species than bottom trawls. Combining these two methods, 33 orders, 65 families, and 130 species of fishes were identified. Perciformes and Clupeiformes, the most abundant orders in the catch, represented 31.5 and 10.0% of the total fish abundance, respectively. The results of ANOSIM and redundancy analyses indicated that the fish community structure varied significantly between summer and winter, however depth and temperature being the main environmental factors influencing fish distribution. The biodiversity index was higher in summer than in winter. Thus, our work provides more detailed seasonal data on biodiversity in the Zhoushan Sea, which is essential for the long-term management and conservation of coastal biodiversity. Compared with traditional survey methods, eDNA determination is highly sensitive, accurate, cost-efficient, and suitable for fish diversity studies in relevant sea areas. Although this approach cannot completely replace traditional methods, our findings demonstrate that it provides a reliable complementary method for assessing fish diversity in marine ecosystems.

Section: Discussionmentioning

confidence: 99%

Combined Use of eDNA Metabarcoding and Bottom Trawling for the Assessment of Fish Biodiversity in the Zhoushan Sea

Zhou¹,

Fan²,

Xia³

et al. 2022

“…The water samples were collected in mid-May, close to the spawning time of black sea bream in Jiangsu, and the results showed that the black sea bream eDNA signals were high in the surrounding area of Jiangsu, which strongly suggests the presence of spawning fish. Previous studies have confirmed the ability of aquatic species spawning ground detection using eDNA (Takeuchi et al, 2019;Wang et al, 2020), for example, the use of environmental DNA monitoring to confirm the results of changes in spawning grounds of small yellow croaker (Larimichthys polyactis) that were first identified by traditional methods (Wang et al, 2020). The mystery spawning region of the Japanese eel Anguilla japonica was eventually discovered and validated by the eDNA approach (Takeuchi et al, 2019).…”

Section: Distribution Of Black Sea Breammentioning

confidence: 92%

Fishery resource monitoring of the East China Sea via environmental DNA approach: a case study using black sea bream (Acanthopagrus schlegelii)

Zhang

Zhou²,

Zhang³

et al. 2022

Self Cite

Understanding fish stock distribution is crucial in the context of sustainable fishery development. Traditional approaches such as net catching, mark recapturing, and visual counting are often time-consuming, less effective, and prone to subjective bias. Recently, environmental DNA (eDNA) technology has made up for the shortcomings of traditional fishery resource survey methods and has been widely used for species monitoring, biodiversity assessment, and biomass estimation. In this study, the eDNA method was used to analyze the potential distribution range of the black sea bream (Acanthopagrus schlegelii) in the East China Sea. The black sea bream-specific primers and probe were designed and applied in the current study. Results showed high black sea bream eDNA concentrations in Dasha fishing ground, Yangtze Estuary fishing ground, and Zhoushan fishing ground. Higher concentrations of black sea bream eDNA were found in water depths approximately 30–40 m. The eDNA hotspots were mainly concentrated at 29°N–33°N, 122°E–125°E, but no significant differences in horizontal or vertical distributions were observed. Temperature is a critical factor in the presence and black sea bream eDNA among environmental variables in the correlation analysis. In addition, a linear formula between environmental factors and the black sea bream eDNA concentration of black sea bream was predicted, which may be helpful for future fishery resource surveys. To summarize, the present paper provides a new idea for marine resource surveys. It also affords a method and theoretical basis for applying the eDNA technology in fishery surveys, which is expected to become an essential tool for fishery resource surveys in the future.

“…Most of the studies focused on a small portion of the geographic range of species. Wang X et al (2020) identified the spawning grounds in Changjiang fishing ground and Zhoushan fishing ground based on environmental DNA analysis, however, the study area was mainly located in the south of Yangtze River Estuary. In this study, the special survey project of spawning grounds provides relatively comprehensive data for delimiting spawning sites in conservation areas.…”

Section: Figurementioning

confidence: 99%

Incorporating egg-transporting pathways into conservation plans of spawning areas: An example of small yellow croaker (Larimichthys polyactis) in the East China Sea zone

Liu

Jin²,

Lan³

et al. 2022

Backward-in-time Lagrangian model can identify potential spawning areas by reconstructing egg drift trajectories, contributing to accurately designing potential priority conservation plans for spawning areas. In this study, we apply this approach to investigate the small yellow croaker (Larimichthys polyactis) with commercial value in China. A two-step spatial random forest (RF) model is used to predict the occurrence probability and abundance of their eggs and describe the optimal ecological range of environmental factors. A priority protection index (BPPI) of the spawning areas is established by combining the sites with the optimal occurrence and abundance and integrating backward tracking pathways. The result indicates that the model with 1-2 day time lags of environmental variables shows the optimum explanatory power. Temperature and salinity are the most important factors affecting oogenesis and show a regime shift in the response curve. They reflect the physiological regulation of parental sexual maturation by the environment. In addition, egg abundance correlates more strongly with chlorophyll-a (Chl a) concentration and depth, suggesting that parents prefer environments with shallow water and high prey density for spawning activities. The egg retrieval shows that the potential spawning sources are distributed near the southeastern part of the oogenesis site, with a maximum egg dispersal distance of no more than 30 km. This finding confirms that the coastal regions of Jiangsu Province are an important spawning ground for the small yellow croaker, making a significant contribution to the productivity and resilience of the fish.