Artificial spawning of common tench Tinca tinca (Linnaeus, 1758), obtained from wild and domestic stocks

The study encompasses three reproduction seasons. Tench spawners caught during the spawning season originated from carp ponds (domestic stock) and a lake (wild stock). Fish were reproduced under controlled conditions after hormonal stimulation with GnRHa-containing pellets combined with metoclopramide (Ovopel) or carp pituitary homogenate (CPH). As a result of hormonal stimulation, eggs were obtained from a larger number of females originating from the lake (71.7%) than those originating from the pond (58.3%), although no other statistical differences were found. A similar relationship was recorded for the spermatozoa motilities (range from 72 to 76%). The obtained results indicate that both investigated reservoirs are suitable for tench broodstock management due to the fact that synchronization of ovulation among different stocks is easy to achieve. For this purpose, among the tested spawning agents, Ovopel could be recommended as being slightly more effective.