caa a22 4500 477116663 CHVBK 20180405111624.0 cr unu---uuuuu 170330e19961201xx s 000 0 eng 10.1007/BF00005052 doi (NATIONALLICENCE)springer-10.1007/BF00005052 Notes on the induced reproduction and development of the tigerfish, Hydrocynus vittatus (Characidae), embryos and larvae [Elektronische Daten] [Gert Steyn, Christo Gagiano, Andrew Deacon, Hein du Preez] Synopsis: In South Africa, the distributional range of tigerfish,Hydrocynus vittatus, has diminished over the past fifty years mainly as a result of migration barriers and reduced river flow. A project to restock traditional tigerfish waters has been envisaged for many years but did not materialise due to an inability to spawn this species artificially. Several hormones were therefore tested for their potency to induce ovulation in this species. Gonadotropin releasing hormones (GnRh) were used in combination with dopamine receptor antagonists. Human chorionic gonadotropin (HCG) was administered in conjunction with catfish pituitary gonadotropin. Both sexes were successfully stripped and the eggs were inseminated artificially. Tigerfish eggs are small (0.65 mm diameter), demersal and slightly adhesive. Hatching occurs 22 h 30 min after insemination and free embryos are pelagic and display continuous vertical movement for a period of three days. Embryonic development was photographed until first feeding, 5 days after hatching. From these results as well as field observations, it is concluded that tigerfish spawns on a sandy substrate in the vicinity of aquatic vegetation. Kluwer Academic Publishers, 1996 Hormonal induction nationallicence Artificial spawning nationallicence Embryonic development nationallicence Rearing of larvae nationallicence Juveniles nationallicence Steyn Gert Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut Gagiano Christo Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut Deacon Andrew Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut du Preez Hein Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut Environmental Biology of Fishes Kluwer Academic Publishers; http://www.wkap.nl 47/4(1996-12-01), 387-398 0378-1909 47:4<387 1996 47 10641 https://doi.org/10.1007/BF00005052 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00005052 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Steyn Gert Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut NATIONALLICENCE 700 1- Gagiano Christo Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut NATIONALLICENCE 700 1- Deacon Andrew Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut NATIONALLICENCE 700 1- du Preez Hein Research Unit for Aquatic and Terrestrial Ecosystems, Department of Zoology, Rand Afrikaans University, P.O. Box 524, 2006, Auckland Park, South Africa aut NATIONALLICENCE 773 0- Environmental Biology of Fishes Kluwer Academic Publishers; http://www.wkap.nl/ 47/4(1996-12-01), 387-398 0378-1909 47:4<387 1996 47 10641 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer