Assessment of Growth, Reproduction, Recruitment and Virtual Population Analysis of Invasive Species, Coptodon zilllii in Garmat Ali River, Iraq

Abstract

Coptodon zillii has been an invasive fish in Iraqi waters since 2007 and now well established and dominating in different water bodies of the country. The aim of this article is to evaluate the growth, mortality, probability of capture, recruitment pattern, reproduction, yield-per-recruit and virtual population analysis of this species in the Garmat Ali River, Iraq from September 2018 and August 2019. The length and weight of the species were between 7.7 cm and 23.2 cm and 50 g to 144.0 g, respectively. The results of the relationship between them indicate positive allometric growth. The population parameters, including asymptotic length (L∞= 27.0 cm), growth coefficient (K= 0.270), and growth performance index (Φ'= 2.294) were computed. The estimated total length at first capture (Lc) was 14.87 cm, and the first maturity (Lm) lengths were 8.2 and 8.4 cm for males and females, respectively. The recruitment pattern of C. zillii was continuous throughout the year with bimodal recruitment. This study showed higher fishing mortality than natural mortality. The current exploitation rate was lowly elevated compared to E0.1 and Emax. Virtual population analysis exhibited that mid-lengths (14-18 cm) were exposed to the highest fishing mortality. Thus, the fishing activities must be increased to obtain higher yields that could be considered from the species for use as animal forage or for export by increasing the fishing activities through increasing fishing efforts and decreasing the mesh-size nets used by the fishermen.