Comparison of different methods of wild vimba bream Vimba vimba (L.) spawning under controlled conditions.

This paper describes a study in which different types of the reproduction of wild vimba bream (Vimba vimba) under controlled conditions were compared. Reproduction was performed by using three methods: spontaneous (natural spawning- NS groups): without hormones but with nests, semi-artificial (S groups) with hormones and nests, and artificial (A groups) with hormones and manual stripping of gametes. In groups S and A, different types of hormonal stimulation were tested: common carp pituitary homogenate (CPH), human chorionic gonadotropin (hCG), and commercial pellets containing mammalian GnRHa and dopamine antagonist-metoclopramide (Ovopel). The number of spawning fish, i.e., spermiating males and ovulating females, were compared depending on the type of breeding and the stimulant used. The lowest number of finally matured fish: spermiating males (67 %) and ovulating females (0 %) were noted in the spontaneously reproduced group. The best method of reproducing wild vimba bream under controlled conditions was the semi-artificial approach with hormonal stimulation and spawning nests, where ovulation rates in hormonally treated groups were between 43 % and 71 %, vs 26-57 % in artificial spawning groups. No ovulation observe in control groups in S and A types of reproduction. The highest embryo survival to the eyed-egg-stage was noted in group A-hCG (average 88.2). A higher value of spawning effectiveness (Se) with the use of the same hormones was obtained for groups S (0.374-0.574) than for groups A (0.252-0.493). In both cases, the highest Se was recorded for Ovopel stimulated fish and the lowest in hCG stimulated groups.