Length–weight relationships for 11 freshwater fish species (Actinopterygii) from four protected areas, northern Vietnam

The length–weight relationships (LWRs) of 11 fish species from one national park and three nature reserves, in northern Vietnam, totaling 737 individuals between October 2018 and November 2021, are described in this study. The following species, representing 11 genera and seven families, were studied: Aphyocypris normalis Nichols et Pope, 1927, Barbodes semifasciolatus (Günther, 1868), Beaufortia pingi (Fang, 1930), Carassius auratus (Linnaeus, 1758), Glyptothorax honghensis Li, 1984, Hemibarbus medius Yue, 1995, Macropodus opercularis (Linnaeus, 1758), Neolissochilus benasi (Pellegrin et Chevey, 1936), Onychostoma gerlachi (Peters, 1881), Opsariichthys minutus Nichols, 1926, Rhinogobius duospilus (Herre, 1935). All regressions were highly significant ( P < 0.001). Positive allometric growth was seen in six species ( b > 3, P < 0.01) and isometric growth in five species ( b = 3, P > 0.05). This is the first report on the LWRs of six fish species, including Beaufortia pingi , Barbodes semifasciolatus , Neolissochilus benasi , Opsariichthys minutus , Glyptothorax honghensis , and Rhinogobius duospilus from four conservation areas. The presently reported study provides foundational data for future stock assessment works and management initiatives in protected areas, as well as facilities comparisons of LWRs from different habitats.