Artificial stripping and embryonic development of the common gudgeon (Gobio gobio L.) and its use in embryo-larval tests – a pilot study
Artificial reproduction with and without hormonal treatment was performed in females of the common gudgeon (Gobio gobio L.) to assess the suitability of this cyprinid species as a fish model for embryo-larval cytotoxic tests. Considering sperm immobilisation tests, the solution for tench was utilizable. The clearing solution designed for the observation of embryonic development in the European catfish was also found suitable for the common gudgeon embryos. The egg and embryonic mortality, embryonic development, hatching and survival rate were examined. Ovulation occurred in 89% of females after the application of the carp pituitary (5 mg/kg) but embryonic mortality reached nearly 100%. The highest embryonic mortality in females with hormonal treatment was observed within 24 hours of development. On the other hand, the reproduction of females without the application of hormonal stimulation was nearly completely successful with mean mortality 60%. The hatching of embryos of females without hormonal stimulation occurred (average values) 71 hours after fertilization and lasted 65 hours. Embryonic development finished within 176 hours. Our pilot study demonstrated that the eggs of common gudgeon were suitable for embryo-larval tests from the 7<sup>th</sup> to the 8<sup>th</sup> embryonic developmental stage.