Length–weight relationships of six fish species from the headstream region of the Dongjiang River, China

Dongjiang River, a main tributary of the Pearl River, is geographically situated in South China. The present study describes the length-weight relationships (LWRs) of six fish species (Acrossocheilus paradoxus, Barbodes semifasciolatus, Onychostoma elongatum, Microphysogobio fukiensis, Microphysogobio kiatingensis, Metzia lineata) from the headstream region of the river including five Chinese endemic species (A.paradoxus, B.semifasciolatu, O.elongatum, Mi.fukiensis, Mi.kiatingensis). Fish species of five genera of the same family were collected quarterly from April 2012 to October 2014 by using non-selective fishing gears: drag nets (5 m, mesh-size 3 cm), drift gillnets (30 x 15 m, mesh-size 5 mm), fish cages (4 m, mouth opening 40 x 40 cm), scoop nets (mesh-size 0.5-1 cm), and electro-fishing (12V, 200 Hz). The parameter a and b in the LWR equations (W = a L-b) ranged from 0.0014 to 0.0228, and 2.89 to 3.18, respectively. Compared with FishBase, this study provides the first LWR records for four cyprinids (A.paradoxus, B.semifasciolatu, O.elongatum, Me.lineata) and a new record of maximum body length for O. elongatum.