Reproductive cycle and sexual maturity size of landed Selene peruviana (Perciformes: Carangidae) on the coasts of the Ecuadorian Pacific

The Peruvian moonfish (Selene peruviana) is an important fisheries resource that is landed in the main fishing harbors of Ecuador. At the local level, little information is available regarding the biology of this species, which hinders the development of management plans. The present study evaluates the reproductive characteristics of S. peruviana such as the size at sexual maturity and reproductive cycle. Specimens were obtained from artisanal and industrial catches from January 2017 to December 2018. The morphometric characteristics, sex, and maturity stage of 886 specimens were determined, and the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn) were estimated. The length-weight relationship and length at sexual maturity (L50) were evaluated with an allometry equation and multi-model analyses, respectively. The mean capture size (total length, TL) was 23.62 cm for males and 22.97 cm for females. A sex ratio (M:F) of 0.70:1.00 (χ2 = 26.28, P < 0.05) was obtained. The allometric factor of the length-weight relationship for both sexes (b) was 2.63 (t = 12.16, P < 0.05), and the coefficient of determination (r2) was 0.89, which suggests that negative allometric growth was present. The L50 (TL) was estimated to be 22.61, 23.86, and 23.27 cm for males, females, and sexes combined, respectively. The monthly GSI, HSI, and Kn values were significantly different (K-W, P < 0.05) among study months. The maximum GSI values were observed in February and March, which constituted the period of highest reproductive activity. The HSI and Kn values exhibited similar trends. The size at sexual maturity was similar to the average catch size, which could indicate that S. peruviana is currently at the limit of its optimal catch size.