Reproductive Dynamics of Three Important Clupeiform Food Fishes in the Min River Estuary and Its Adjacent Nearshore Waters, China

Abstract

AbstractReproductive dynamics of three important clupeiform food fishes (Gray’s Grenadier Anchovy Coilia grayii, Osbeck’s Grenadier Anchovy Coilia mystus, and Chinese Gizzard Shad Clupanodon thrissa) were studied in the largest estuary of Fujian Province, China: the Min River estuary and its adjacent nearshore waters. Samples were collected from May 2017 through July 2020 using trammel nets and trawlers. Females were observed to be significantly larger than males for Gray’s and Osbeck’s grenadier anchovies but not for Chinese Gizzard Shad. The overall sex ratios of all three species showed a significant female bias. Gonad histology was applied to determine spawning season, peak spawning season, and length at 50% maturity for females and males. The spawning season of females lasted from April to September (peak spawning season in April–July) for Gray’s Grenadier Anchovy, from March to September (peak in March–June) for Osbeck’s Grenadier Anchovy, and from April to July (peak in May–July) for Chinese Gizzard Shad. Spawning seasons of males were similar to those of females. The estimated SLs at 50% maturity for females and males, respectively, were 11.3 and 9.4 cm for Gray’s Grenadier Anchovy, 12.7 and 10.4 cm for Osbeck’s Grenadier Anchovy, and 12.7 and 11.6 cm for Chinese Gizzard Shad. The spawning grounds for these species were located for the first time: in the Min River estuary for Gray’s Grenadier Anchovy, mainly in the adjacent nearshore waters and extending to the estuary for Osbeck’s Grenadier Anchovy, and mainly in the lower reaches of the Min River and extending to the estuary for Chinese Gizzard Shad. As important food fishes in the region, stocks of these three species have shown certain degrees of overexploitation; therefore, stock assessments and management plans are necessary to achieve their sustainable fisheries.