Abstract

COLLAZOS-LASSO, Luis F.; GUTIERREZ-ESPINOSA, Mariana C.  and  RESTREPO-BETANCUR, Luis F.. Cachama blanca larvae’s survival, Piaractus brachypomus Cuvier 1818, in experimental temperature changes. Orinoquia [online]. 2014, vol.18, suppl.1, pp.193-197. ISSN 0121-3709.

Cachama blanca is the native fish species with the highest production in Colombia, however obtaining seed is still limited, mainly because of the reproductive seasonality of the species and the survivals low hatchery, which consists on planting larvae in ponds where subscribers remain to fry, previous acclimatization. The aim of this study was to establish the range of comfort and response times adjusting to changes in experimental temperature, taking the survival of cachama blanca larvae as an indicator. Trials were conducted at the Instituto de Acuicultura de la Universidad de los Llanos (IALL). 1020 cachama blanca larvae of 168 post-hatching hours were used, obtained by induced breeding carp pituitary extract, fed with artemia at 72 HPE (C/6 h). Water quality incubator (Woynarovich type) was: temperature 27 ± 0.4 °C; pH 6.5 ± 0.2; O2 6 ± 0.4 mg / l; hardness 30 ± 5 mg; the larvae were collected and contained in six beakers (40 ml water) arranged in a thermal incubator (Rev. Scien. Mod. RS-IF-201) with previous calibration temperature guaranteeing experience. Each temperature was treated and each beaker a replica (15 larvae). Counting the larval survival of each of the replicas it was performed every five minutes for one hour; Results: the comfort range was established between 22-29 °C, lower stress range between 18-22 °C, the range between 29-32 °C higher stress, lower from 18°C critical range, lethal temperature 50 was established in 9,5 °C and the lethal temperature below 6 °C (for temperatures between ranges presented no statistically significant differences were found in relation to the survival/Alpha=0,05).

Keywords : Fish; characins; acclimatization; stress; temperature comfort.

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