In this study, laboratory reared Cirrhinus molitorella from hatching through to the juvenile stage were used to validate daily increment deposition. Lapilli were suitable for ageing C. molitorella. The slope of the linear relationships between increment counts and age was not significantly different from 1 (n = 258, P > 0·05), indicating that growth increments are deposited daily. The first increment following the first-feeding check formed 3 days post hatch (dph). One hundred and twenty-three juveniles, ranging from 36·4 to 84·7 mm in body length (LB ), were collected in the Pear River estuary from July to January in both 2014 and 2015 and used to estimate growth rate. The core in the lapillus, consisting of a single primordium, a diffuse area and the first-feeding band, was followed by 20 narrow and poorly contrasted daily increments. Thereafter, increments were wide and well-defined, and, finally became less distinct, but still homogenous after c. 53 dph. The mean increment width increased to the 29th increment and stayed relatively constant up to the 35th increment and then, gradually declined to the edge of the otolith. Wild juveniles were aged from 69 to 178 dph and hatched from the 15 February to 2 September. Growth rate was estimated from the adjusted linear regression of LB on age: LB = 4·37 + 0·44A (r2 = 0·60), where A = age. The radius of the core and the regularity and resolution of the increments showed some differences between reared and wild fish. These results are of value for the further study of early life traits and recruitment of C. molitorella.
Keywords: Cyprinidae; Pearl River; age; juvenile; lapilli; larvae.
© 2017 The Fisheries Society of the British Isles.