Efecto del pH sobre la proporción de sexos, el crecimiento y la sobrevivencia del guppy Poecilia reticulata Peters, 1859

Abstract

The absence of information related to the effect of water pH on the guppy Poecilia reticulata sex ratio is notorious. In this study the influence of the pH on sex ratio, survival and growth of juvenile guppy was analyzed. The one day old juveniles fish were kept 18 weeks in three pH treatments: acid (6.2-6.5), neutral (7.0-7.3) and basic (8.4-8.8). In each treatment 45 organisms were evaluated and were fed ad libitum. The temperature and oxygen were maintained in 24.6+-0.4°C and 6.86+-0.05mg O/I. Parameters such as total length, standard length and weight were registered every two weeks. When the experimental period concluded, the growth was estimated. Results indicated that a basic pH environment induced masculinization in a ratio of 1.86:1 and a survival rate of 95.5% was observed. In contrast a neutral pH environment promoted high ratios females to 2:1 and a survival rate of 53.3%. The growth in weight and size analysis indicated that females, of any treatment, were stoutter than the males.