Growth and Reproduction of bluefin searobin (Chelidonichthys spinosus) in the Geoje Island of South Korea

Abstract

A total of 557 bluefin searobin Chelidonichthys spinosus were collected from Beam trawl during the period from October 2017 to September 2018 in the Geoje Island of South Korea. The size of the samples ranged from 9.3 to 40.7 cm total length. The sample were composed of 361 (64.81%) females, 196 (35.18%) males, with female to male ratio of 1.8:1. The gonad somatic index (GSI) was examined to determine the spawning season. Spawning season of C. spinosus was from February to March. Based on proportions that over mature in gonad stage, length at sexual maturity (L_(50%)) of female was approximately 23.21 cm. The length-weight relationship was calculated as BW=0.0111〖TL〗^2.956 (n = 557, r^2 = 0.9781) for all samples, BW=0.0092〖TL〗^3.01 (n = 361, r^2 = 0.9765) for females and BW=0.0147〖TL〗^2.862 (n = 196, r^2 = 0.9796) for males. The age of the sampled individuals, which ranged from 2 to 9 years, was estimated by using the count of growth ring recorded on the otolith. Length-at-age data were fitted using von Bertalanffy growth model. The estimated von Bertalanffy growth functions were 〖TL〗_t=50.58(1-e^(-0.12(t-0.77) )) for female, 〖TL〗_t=59.15(1-e^(-0.10(t-0.73) )) for male and 〖TL〗_t=55.39(1-e^(-0.11(t-0.71) )) for combined sex. Growth performance Index (φ) was estimated from von Bertalanffy growth parameter. Females and males was estimated to be 2.50 and 2.54, respectively. Growth performance Index (φ) of combined sex was 2.52.