Length-weight relationships and condition factor of five endemic fish species from Nandu and Wanquan Rivers in Hainan Island, China

Abstract

Length-weight relationships (LWRs), length-length relationships (LLRs), and condition factor were estimated for Puntiussemifasciolatus (Günther, 1868), Acrossocheilus iridescens (Nichols and Pope, 1927), Plesiomyzon baotingensis (Zheng and Chen, 1980),Hemibagrus hainanensis (Tchang, 1935) and Glyptothorax hainanensis (Nichols and Pope, 1927) obtained from Nandu and WanquanRivers in Hainan Island during June 2017 to April 2019. Fish samples were collected by a combination of methods including multinetgillnets (20 m in length, 1.5 m in height, there monofilament panels of mesh sizes: 1.0, 6.0, 12.5 cm), benthic large bag nets (5 meterslong, stretching mesh size: 0.5 cm). The LWRs and LLRs of all species studied were well correlated ($R^2$ > 0.95). The b values ranged from2.8285 for H. hainanensis to 3.0815 for P. baotingensis. The 5 LWRs and LLRs are presented to FishBase for the first time. Additionally,condition factor of P. semifasciolatus, A. iridescens, P. baotingensis, H. hainanensis and G. hainanensis were severally 11.85 ± 1.34, 1.86± 0.18, 2.05 ± 0.28, 1.36 ± 0.33, and 2.02 ± 0.35, respectively. This study aims at facilitating fishery management or conservation byproviding essential data for the regulation of catches and estimation of biomass in Nandu and Wanquan Rivers in Hainan Island.