INVESTIGADORES
GARCIA DE SOUZA Javier Ricardo
congresos y reuniones científicas
Título:
Temperature effect on sex determination in pejerrey (Odontesthes bonariensis) in the wild
Autor/es:
DEL FRESNO PAMELA; GARCIA DE SOUZA JAVIER RICARDO; COLAUTTI DARÍO CÉSAR; BERASAIN GUSTAVO; MIRANDA LEANDRO
Lugar:
Manaos
Reunión:
Simposio; 11th International Symposium on Repreductive Physiology of Fish; 2018
Institución organizadora:
National Institute for Amazonian Research (INPA ? Manaus/AM ? Brazil)
Resumen:
IntroductionIt is known that pejerrey (Odontesthes bonariensis) has a strong temperature sexdetermination (TSD). Experimentally, it was demonstrated that the proportion of femalesgradually changes from 100% at 15?19C to 0% at 29C when larvae are reared at differenttemperatures between 1 and 5 weeks after hatching (TSD window). The objective of thisstudy was to analyze the effect of water temperature on sex ratio in pejerrey larvae in thewild.MethodsNewly hatched pejerrey larvae were sown in floating cages of 1 m3 in September, October,November and December 2016 in La Salada de Monasterio lake (35° 44?S, 57° 53?O),Buenos Aires province, Argentina. Water temperature (WT) per hour was recorded throughdata loggers placed in the cages. After three months 50 juveniles per cage were captured andtaken to the laboratory. They were sacrificed on ice and the gonads were observed using amicroscope to establish the phenotypic sex. Sex proportions were calculated and analyzed inrelation to the water temperature recorded during TSD window.Results and DiscussionIn the juveniles of September cages, the proportion of males, was 53% (mean WT duringTSD window: 13.9 ± 1.3° C), of October: 43% (mean WT: 18.6 ± 3.0° C), of November:55% (22.1.7 ± 1.5° C) and of December: 65% (25.7 ± 1.9° C). These results showed that theproportion of males at low water temperatures (September and October cages) mismatch withthe experimental proportions where all females were observed. On the other hand, theproportion of males at higher water temperatures (November and December cages) wassimilar to the found in previous laboratory experiments.ConclusionThese findings lead us to conclude that in the wild and especially at low water temperatures,another factor (food availability, thermal fluctuation, etc) besides temperature could be relatedto sexual determination in pejerrey
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