EUROPEAN CATFISH (SILURUS GLANIS L.) REPRODUCTION OUTSIDE OF THE SPAWNING SEASON
The Stanisław Sakowicz Inland Fisheries Institute in Olsztyn, Poland
ABSTRACT. The aim of this work was to develop methods of artificial European catfish reproduction outside of its natural spawning season using thermal and hormonal stimulation. Ovulation was induced with combined hormonal stimulation using a priming dose of Ovopel (0.3 granules in one dose or 0.2 and 0.3 granules in two doses per kg of female body weight) and a resolving dose of carp pituitary extract (CPE) (3 mg per kg of female body weight). The latency period between the doses was 24 hours. The males were stimulated with one dose of Ovopel (1 granule per kg of body weight). The results obtained indicated that the application of the appropriate thermal and hormonal stimulation, without light stimulation, can induce artificial spawning in the European catfish between January and August. It was revealed that the time between the injection of the resolving dose and egg collection decreased over this period. Thus, ovulation could be stimulated faster than in winter and spring. The number of eggs obtained in pre-season spawning was greater when the thermal treatment was longer. The results obtained indicate that the application of Ovopel in two stimulation doses instead of one was advantageous for the effectiveness of European catfish pre-season spawning, the number of eggs obtained as well as its survival. The results obtained during artificial European catfish reproduction conducted before, during, and after its natural spawning period were comparable.
Key words: EUROPEAN CATFISH (SILURUS GLANIS), OUT-OF-SEASON SPAWNING, REPRODUCTION
Dr inż. Dariusz Ulikowski, Instytut Rybactwa Śródlądowego, Doświadczalny Ośrodek Zarybieniowy „Dgał“, 11-610 Pozezdrze, Pieczarki 50,
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