Drivers of temporal variations in fish assemblages from mangrove creeks in Beihai, southern China

Mangroves are regarded as important settlement grounds and nurseries for fishes due to the sheltered nature of these ecosystems. To identify the drivers of temporal variations in fish assemblages, seasonal variations of fish assemblages and environmental variables were investigated in Nanliu River Estuary, China, from July 2019 to May 2020. In total, 17,680 individuals weighing 24,724.73 g belonging to 23 families and 45 species were collected. The dominant species were Ambassis urotaenia, Mugil cephalus, Coptodon zillii, Gambusia affinis, and Bostrychus sinensis. Fish assemblages were significantly different in seasonal periodicity according to the results of nonmetric multidimensional scaling (NMDS) and permutational multivariate analysis of variance (PERMANOVA). Kruskal-Wallis test results revealed that species richness, fish abundance, and biomass were significantly different, seasonally. The highest number of fish specimens captured was recorded in winter and summer, while the highest biomass was observed in autumn. Different ecological types of fish utilized mangroves in different ways. Hence, the findings in this study are instrumental in understanding and the conservation of mangroves even coastal wetland and fish resources in the process of mangrove restorations.

Automated summary

This study investigated the seasonal variations of fish assemblages and environmental variables in the Nanliu River Estuary, China, and found significant differences in fish assemblages across seasons. Different ecological types of fish utilized mangroves in different ways.