Embryogenesis and early larval development in bocachico (Prochilodus magdalenae) in Colombia

Abstract

Abstract Background The bocachico (Prochilodus magdalenae) is a migratory freshwater fish and one of the main species of Colombian continental fishery. Interest in it is due to the fish’s excellent reproductive characteristics and sociocultural value in its native region. As part of native fish species repopulation programs carried out by the GIPEN research group of the San Silvestre fish farm and ISAGEN, the present study aimed to characterize the embryogenesis and early larval development of bocachico from zygote phase to the exogenous feeding period, using morphological and histological landmarks. Results Embryos were obtained by fertilization from hormonally induced, wild-caught brood stock, and subsequent development was monitored at temperatures coinciding with native conditions. Embryonic development from fertilization to hatch lasted 13 h. This included the following stages: zygote, cleavage, blastula, gastrula, segmentation and organogenesis, pharyngula and hatching. Larvae emerged with unpigmented eyes; the cephalic area and the eye primordium were more developed at 1 day post-hatching. At 2–3 days post-hatching, the somites formed myotomes and pharyngeal arches were present as well as an undifferentiated digestive tract (endogenous feeding period). At 3–4 days post-hatching, the mouth was open, and the oral valve was developed; the mouth was continuous with the esophagus and the rest of the digestive system (beginning of the endo–exogenous feeding period). The yolk was observed for up to 9 days post-hatching (end of the endo–exogenous feeding period and beginning of the exogenous feeding period). Conclusion To the best of our knowledge, this is the most comprehensive analysis made of the development of the bocachico to date, from early embryonic development to the larval phase, and this research will contribute to improving the knowledge of the developmental intervals of this species, the critical stages in feeding phases, as well as a more concrete approximation of when the fish is suitable for repopulation based on its morphological development.