Abstract

AYA-BAQUERO, Elizabeth; ARIAS-CASTELLANOS, José A.  and  COLLAZOS-LASSO, Luis F.. Maduración gonadal de la cucha mariposa, Glyptoperichthys gibbiceps (Kner, 1854) (Pisces: Loricariidae), en el río Guaviare, Colombia. Orinoquia [online]. 2016, vol.20, n.2, pp.15-22. ISSN 0121-3709.

Glyptoperichthys gibbiceps (sailfin pleco), is one of the largest loricariids (up to 50 cm TL) in the Orinoco River basin in Colombia of which little is known of their natural history. To know the reproductive cycle, bimonthly collections for twelve months of adult specimens were made in a section of the Guaviare River (N 02 ° 37 ‘52.7 "W 072 ° 42’ 28.08", 196 m). Specimens were killed on site, after anesthesia, recording morphometric and weight measurements, and then eviscerated. The gonads were weighed, and the sex and stage of sexual maturity of individual gonads were identified. A sample of the middle portion of each gonad was fixed for 24 h in buffered formalin and transferred to 70% ethanol until processed for standard histological analysis of tissues stained with H&E. A total of 26 females weighing 495.7 ± 52.9 g and 36.6 ± 4.1 cm TL, and 9 males of 676.7 ± 192.8 g and 36.6 ± 4.1 cm TL, (sex ratio 3 females to 1 male) were studied and four main stages were used to describe gonadal development (resting stage , developing or maturing, ripe or matured, and pre-reproductive juveniles). At rest the ovaries and testicles were small translucent and difficult to differentiate. The maturing ovaries were slightly differentiated, globular, translucent yellow containing oocytes with diameters of 2768 ± 372μm; the testicles had a rosy coloration. The mature ovaries were globular of an intense brilliant yellow, and the oocytes attained diameters of 4155 ± 96μm, and were visible to the naked eye; the testicles were white and apparent. The pre-reproductive juveniles or individuals with immature gonads were found throughout the year. In the reproductively active females and males the gonads mature synchronously once a year and spawning activity occurred during periods when water levels were rising. The average fecundity was estimated at 1483 ± 380 eggs / mature female. The oocyte and sperm cycles were very similar to those described for other Loricariids.

Keywords : gonadal maturation scale; oocyte diameter; oocyte maturation; reproductive cycle; sperm maturation.

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