Length–weight relations of 11 goby species (Actinopterygii: Gobiiformes) from mangroves along the Ba Lat estuary of the Red River, Vietnam

Presently reported study examined the length–weight relations for 11 goby species collected from a mangrove estuary of the Red River, Vietnam. A total of 1097 individuals of the following species, representing three goby families, were analyzed: Butis butis (Hamilton, 1822); Butis koilomatodon (Bleeker, 1849); Acentrogobius moloanus (Herre, 1927); Acentrogobius viridipunctatus (Valenciennes, 1837); Apocryptodon madurensis (Bleeker, 1849); Aulopareia unicolor (Valenciennes, 1837); Glossogobius giuris (Hamilton, 1822); Gobiopsis macrostoma Steindachner, 1861; Mugilogobius abei (Jordan et Snyder, 1901); Tridentiger barbatus (Günther, 1861); and Tridentiger trigonocephalus (Gill, 1859). The regression slope values (b) ranged from 2.909 to 3.621. The majority of species had positive allometric or isometric growth pattern with b ≥ 3, except for only one species (G. giuris) which had a negative allometric growth with b = 2.909. This study provided the first LWR information of four gobies that have not been reported in FishBase yet. Besides, the reference for LWRs of other gobies at an ecologically important area like Ba Lat Estuary is also provided.

Length–weight relations of 11 goby species (Actinopterygii: Gobiiformes) from mangroves along the Ba Lat estuary of the Red River, Vietnam

Presently reported study examined the length–weight relations for 11 goby species collected from a mangrove estuary of the Red River, Vietnam. A total of 1097 individuals of the following species, representing three goby families, were analyzed: Butis butis (Hamilton, 1822); Butis koilomatodon (Bleeker, 1849); Acentrogobius moloanus (Herre, 1927); Acentrogobius viridipunctatus (Valenciennes, 1837); Apocryptodon madurensis (Bleeker, 1849); Aulopareia unicolor (Valenciennes, 1837); Glossogobius giuris (Hamilton, 1822); Gobiopsis macrostoma Steindachner, 1861; Mugilogobius abei (Jordan et Snyder, 1901); Tridentiger barbatus (Günther, 1861); and Tridentiger trigonocephalus (Gill, 1859). The regression slope values (b) ranged from 2.909 to 3.621. The majority of species had positive allometric or isometric growth pattern with b ≥ 3, except for only one species (G. giuris) which had a negative allometric growth with b = 2.909. This study provided the first LWR information of four gobies that have not been reported in FishBase yet. Besides, the reference for LWRs of other gobies at an ecologically important area like Ba Lat Estuary is also provided.

Lateral Export of Dissolved Inorganic and Organic Carbon from a Small Mangrove Estuary with Tidal Fluctuation

The significance of aquatic lateral carbon (C) export in mangrove ecosystems highlights the extensive contribution of aquatic pathways to the net ecosystem carbon budget. However, few studies have investigated lateral fluxes of dissolved organic carbon (DOC) and inorganic carbon (DIC), partly due to methodological difficulty. Therefore, we evaluated area-based lateral C fluxes in a small mangrove estuary that only had one exit for water exchange to the coast. We sampled water from the mouth of the creek and integrated discharge and consecutive concentration of mangrove-derived C (ΔC). Then, we estimated the area-normalized C fluxes based on the inundated mangrove area. DIC and DOC concentrations at the river mouth increased during ebb tide during both summer and winter. We quantified the ΔC in the estuary using a two-component conservative mixing model of freshwater and seawater. DIC and DOC proportions of ΔC concentrations at the river mouth during ebb tide was between 34% and 56% in the winter and 26% and 42% in the summer, respectively. DIC and DOC fluxes from the estuary were estimated to be 1.36 g C m−2 d−1 and 0.20 g C m−2 d−1 in the winter and 3.35 g C m−2 d−1 and 0.86 g C m−2 d−1 in the summer, respectively. Based on our method, daily fluxes are mangrove area-based DIC and DOC lateral exports that can be directly incorporated into the mangrove carbon budget.