Influence of temperature on fertility, growth rates, and reproductive success on selected species of Apistogramma (Teleostei, Cichlidae)
Abstract: The temperature of the environment has significant influence on growth and reproduction in the species of Apistogramma. High temperatures cause reduced survival of the offspring, reduction of growth (size and weight), number of eggs and clutches, and size of eggs, a possible reason being a temperature-induced deficiency of energy. Six month old A. cacatuoides shows optimal growth (females up to 46 mm TL, males up to 76 mm TL) and gain of weight at 26°C. Temperatures lower than 25°C have a weak negative effect, those in excess of 28°C a substantial negative effect on growth. Female A. cacatuoides matures at an age between 140 and 350 days. This is not directly linked to temperature, but indirectly via the temperature-influenced reaching of a length of 30 to 34 mm TL, at which females spawn for the first time. The number of eggs per clutch and the number of clutches per female depend on temperature. Both low (20 to 22°C) and high (29 to 30°C) temperatures results in reduced numbers in comparison to intermediate temperatures (25 to 28°C). Eggs produced at low temperatures (< 25°C) are about one fifth larger than those produced at high temperatures (> 28°C). The reproductive success in the field seems not to be significantly influenced by temperature, but from predation and the female’s capacity for sheltering the offspring in its mouth.