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This study evaluated the potential effect of stock enhancement on a coastal ecosystem. Based on data collected from the 2020 bottom trawl survey and literature information, an Ecopath model was constructed containing 19 functional groups representing the coastal area of southern Zhejiang, China. Jellyfish (Rhopilema esculenta) and black seabream Acanthopagrus schlegelii were selected as target-enhancing species based on their extensive juvenile release records. The maximum carrying capacity of these two species was estimated by static Ecopath and the potential ecological effects of enhancement activity for these two species were evaluated by the Ecosim routine. The trophic level (TL) of the functional groups in the coastal area of southern Zhejiang ecosystem ranged from 1 (primary producers) to 4.56 (sharks). The mean transfer efficiency of the coastal area ecosystem of southern Zhejiang was 8.71%, in which the relatively low transfer efficiency from TL2 to 3 was considered the main bottleneck that limited the biomass of higher TL species in this ecosystem. System characteristics indicated that the coastal area ecosystem of southern Zhejiang was vulnerable to disturbances and had low recovery ability. Enhancement simulation results indicated that the enhancement of jellyfish and black seabream had a partial impact on the functional groups of the ecosystem. Both jellyfish and black seabream enhancements adversely affected most groups of fish, cephalopods, and crabs, while jellyfish release stimulated the biomass of crabs. Ultimately, the present study indicates that the enhancement of black seabream decreased the total fish biomass via complex trophic interactions in the food web. Additionally, this study shows that recapture rates might not be sufficient to evaluate the net effect of stock enhancement, and therefore highlight the importance of ecosystem-based assessments for stock enhancement. [Display omitted] • Ecosystem-level effects of different stock enhancement strategies were analyzed. • An ecosystem model represents the southern Zhejiang coastal area, China, was constructed. • The enhancement of Jellyfish and Black seabream had partial impacts on the functional groups of this ecosystem. • Recapture rates might not be sufficient to evaluate the effect of stock enhancement. [ABSTRACT FROM AUTHOR]

Vinasse is the waste liquid of molasses fermentation for alcohol production from sugarcane mills. The adequate utilization and treatment for vinasse have received increasing attention. Among the alternatives considered for the reuse of vinasse, irrigation in sugarcane fields is most common solution. However, few researchers consider the impact on the soil fertility, soil heavy metals content and soil microbial diversity by long-term application of vinasse in the fields. In order to evaluate the cumulative impact arising from the long-term application of vinasse, different treatments, viz., (1) soils not irrigated with vinasse, (2) soil irrigated with vinasse for 2 years, (3) soil irrigated with vinasse for 7 years, (4) soil irrigated with vinasse for 13 years, (5) soil irrigated with vinasse for 18 years, have been applied to sugarcane fields in Shangsi County, Guangxi, China. The pH, organic matter, total and available N, P, K, the concentration of Cu, Pb, Cr, Zn, Ni, Cd and As, as well as the diversity of microbial community of the soil samples were determined. The results showed that after long-term irrigation by vinasse, soil acidification was observed, organic matter, N and K content increased, but no significant changes in the increase in P content were observed. The potential ecological risk of Cd, Cr, Pb, Zn, Cu, Ni and As was low, indicating that accumulation of heavy metals in the soil was negligible when long-term irrigation with vinasse was practiced. The diversity of microbial community expressed as relative abundance of the predominant species in irrigated soil was slightly reduced due to influence by the physicochemical properties of soil, especially soil pH. Consequently, the proper management of vinasse irrigation and periodic monitoring of soil quality parameters are required to ensure safe and long-term irrigation. [ABSTRACT FROM AUTHOR]

This study investigated the feeding habits of black croaker (Atrobucca nibe) to fully understand its role in the food web in southern coastal waters of Zhejiang, China. In total, 225 black croakers were collected in a bottom trawl survey, of which 195 were used for the stomach contents analysis and 30 for high-throughput sequencing (HTS). Both approaches showed that the main prey was shrimp, with Alpheus japonicus being the most predominant. In addition, black croaker also fed on other benthic species, suggesting that it was a demersal predator. Feeding intensity also varied with black croaker body length, as did prey preference, from small-sized species to larger species with increases in fish size; in addition, prey species were more diverse in the large-bodied prey group. Canonical correspondence analysis indicated that the feeding habit of black croaker was most significantly correlated with temperature and dissolved oxygen. HTS was shown to be a feasible high precision semi-quantitative analytical approach, although it must be combined with morphological methods to obtain more complete feeding data; thus, it could provide an effective scientific basis for feeding ecology studies of marine organisms. • The feeding habits of common economic fish in China were analyzed. • A comprehensive analytical method combining stomach content analysis and high-throughput sequencing was applied. • The influence factors of feeding habits were analyzed as explanatory variables in canonical correspondence analysis. • The feasibility of applying high-throughput sequencing to the feeding habits analysis of black croaker was confirmed. [ABSTRACT FROM AUTHOR]