Effects of a luteinizing hormone-releasing hormone analogue (LHRHa) on the reproductive performance of spotted sand bass Paralabrax maculatofasciatus (Percoidei: Serranidae)

Abstract

Hormonal induction of spotted sand bass Paralabrax maculatofasciatus, was investigated in order to induce and synchronize spawning. Three experiments were conducted using wild fish captured in the Gulf of California: 1) LHRHa (luteinizing hormone-releasing hormone analogue) induced spawning with concentrations of 25, 50, 100 µg kg-1 and saline solution, 2) Effects of LHRHa on motility and sperm density, and 3) Induction and incubation of spawns obtained using LHRHa. In experiments 2 and 3 using concentrations of 12.5, 25, 50 µg kg-1 and saline solution. In experiment 1, a higher spawning ratio was observed for the concentration of 25 µg kg-1; however, no significant differences were observed in the proportion of floating (viable) eggs. In experiment 2, significant differences (P < 0.05) were observed in duration of sperm motility and sperm density, with highest duration registered for wild fish (control group) and highest density registered for laboratory control group and concentration of 12.5 µg kg-1. In experiment 3, significant differences (P < 0.05) were observed between treatments in volume of spawned eggs and proportion of fertilized eggs, with higher values shown for the concentrations of 50 and 12.5 µg kg-1, respectively. Survival at hatching and proportion of live yolk-sac larvae were significantly higher (P < 0.05) for the concentration of 12.5 µg kg-1. LHRHa was effective in inducing and synchronizing the spawning of spotted sand bass, a process which will be used for massive egg production.