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A recent study based on gonad histology revealed that the existence of the spawning grounds for Gray's grenadier anchovy (Coilia grayii) and Osbeck's grenadier anchovy (C. mystus) in the Min River Estuary, the largest in Fujian Province, southern China. Further confirming their natal sources and migratory patterns is essential to understand their life histories. We used otolith microchemistry to assess the origins and habitat uses of 23 C. grayii and 22 C. mystus , collected the Min River Estuary and the adjacent waters. The results showed that C. grayii spawned in both freshwater (n‍ = 14) and brackish water (n = 9), and C. mystus spawned mainly in brackish water (n‍ = 20) with minor in freshwater (n‍ = 1) and marine water (n‍ = 1). The migratory patterns of C. grayii (four types) and C. mystus (five types) were diverse, mainly exhibiting anadromous and semi-anadromous behaviors. The first migratory behavior of C. grayii and C. mystus occurred within the age of the first year. The findings have significant implications for fishery stock management of the Min River Estuary and its adjacent waters. • Movements between the Min River Estuary and the adjacent waters were studied for Coilia grayii and C. mystus (Engraulidae). • Otolith microchemistry was used to assess natal sources and migratory patterns. • C. grayii and C. mystus have different natal sources and migratory patterns. • The ages of the first migratory behavior were assessed for C. grayii and C. mystus. • Understanding fish movements are important for effective fishery management. [ABSTRACT FROM AUTHOR]

Length‐weight relationships (LWRs) were estimated for 11 fish species from the Min River Estuary and its adjacent waters, Fujian Province, China. All samples were collected using gillnets (mesh size 45 mm) and bottom trawls (mesh sizes 45 mm at the main webbing and 25 mm at the cod end) seasonally in 2017 and 2018. The parameters for the LWRs were estimated, along with the basic Statistical analyses for total length and weight ranges as well as the 95% confidence intervals for the intercept (a) and the slope (b) of the regression lines. Further, the coefficient of correlation indicated that the LWRs were highly significant (all r2 >.95, p <.001). This study provides the new maximum total lengths (TLmax) for Coilia grayii (33.0 cm), Johnius taiwanensis (20.9 cm), Johnius trewavasae (22.0 cm) and Cynoglossus sibogae (22.0 cm). [ABSTRACT FROM AUTHOR]

Otolith microchemistry allows reconstructing the life histories and understanding the habitat uses of fishes. In this study, the relationship of Sr:Ca ratios and salinity from various environments, i.e. freshwater of the Min River, brackish water of the estuary and seawater of the coastal marine (Fujian Province, China), were built, revealing a significant positive correlation (p < 0.05). A total of 29 adult Chinese gizzard shad Clupanodon thrissa were collected in 2017–2020 for otolith (sagitta) microchemistry. The specimens were only collected from the Min River and the estuary, with none from the coastal marine regions despite same efforts input. The results confirmed that all 29 individuals hatched in either freshwater or brackish water. Four contingents were recognized based on various life histories, including three migratory contingents (Types A-C, N = 26) and one freshwater residential contingent (Type D, N = 3). The three migratory contingents were the freshwater-brackish migratory contingent (Type A, N = 12), the brackish-freshwater migratory contingent (Type B, N = 10) and the brackish-variable migratory contingent (Type C, N = 4). Only a small proportion of C. thrissa individuals (N = 4) migrated to seawater habitat during the first few months of lifetime, and most individuals preferred freshwater habitat during the first year. There were no significant differences between life history pattern and sex (p = 1.00), and between the number of fish migratory times crossing different habitats and age (p = 0.84). The lower reaches of the Min River and the estuary are confirmed to be important spawning grounds for C. thrissa , based on otolith microchemistry of this study and gonad histology of a previous examination. The findings have significant implications for the Min River and the estuary protection and fishery stock management. [ABSTRACT FROM AUTHOR]