Idoneidad del hábitat de Amatitlania nigrofasciata y caudales ecológicos del río Cara Sucia, El Salvador

El cálculo de caudales ecológicos de ríos en El Salvador, se basa en metodologías hidráulicas orientadas al uso del agua, sin tomar integridad y función ecológica. Se presenta el estudio de caso del río Cara Sucia, donde se determinó el caudal ecológico por metodologías eco-hidráulicas utilizando a Amatitlania nigrofasciata como bioindicador. Se estimó la curva de idoneidad de hábitat de A. nigrofasciata con profundidad, velocidad del agua y tipo de sustrato. La especie prefiere hábitats con profundidades de 0.2-0.7 m (juveniles y adultos) y hasta 0.8 m época lluviosa; sobre sustratos rocosos, hojarascas y vegetación sumergida, con velocidades de 0.3-0.6 m/s en ambas épocas. La simulación del ambiente físico mostró caudales de 1.0 m3/s con condiciones habitables para la especie y hábitat potencial con caudales de 2.2 m3/s (juveniles) y 5.0 m3/s (adultos). Condiciones de estrés hídrico por cambio climático y actividades antropogénicas afectarán este ecosistema, eliminando funciones ecológicas y económicas locales.

Convict cichlid parents that stay with the same mate develop unique and consistent divisions of roles

Previous studies, largely on avian species, have suggested that pairs that are permanently monogamous and have biparental care develop a coordination over time that enhances offspring survival. If this is the case, we predicted that a parent involved in biparental care would develop a pattern of biparental care specific to a particular mate and remain consistent in that pattern over time but would lose this pattern if it were to change mates. We tested this prediction with the convict cichlid fish (Amatitlania nigrofasciata) which has biparental care that is both complex and flexible. In this species, each parent can perform all parental roles but typically shows a division of labor in which males typically defend against offspring predators while the female typically provides direct care to the offspring. At various times, the parents briefly switch roles. Our experiments revealed that pairs that remained together for two consecutive broods were more consistent in their parental behaviors, including time they spent near the intruder and in the nest compared to pairs that were comprised of individuals that had previously mated with other partners. Also individuals that remained with the same partner were also more consistent as a parental unit, maintaining their sex-specific roles of males defending aggressively against an intruder and females spending more time directly caring for young. While our experiment clearly support our prediction that individuals do develop unique coordination with specific individuals, convict cichlids in nature appear to be largely serially monogamous in which they mate only once before changing partners. Thus, it is likely this coordination may be available in many species that have biparental care but become adaptive when repeated matings become common.

Investigation on the Global Distribution of Invasive Fish Species, Convict Cichlid Amatitlania Nigrofasciata (Perciformes, Cichlidae) Over the Past Years with Emphasis on Iranian Inland Waters

The aim of this study was to investigate the global distribution of a non-indigenous and invasive fish species, the convict cichlid Amatitlania nigrofasciata, over time, with an emphasis on the inland waters of Iran. The results showed that the distribution range of the convict cichlid was initially based in Central America. Then, the distribution range of this species expanded to parts of North America. Finally, this fish species was introduced to other parts of the world such as Australia, Israel, Italy, Colombia, Germany, Peru, Slovakia, Japan, Indonesia, the Philippines, and Iran due to its extensive ability to spread. So far the presence of A. nigrofasciata has been reported in two domestic basins in Iran, namely Hormuz and Namak Lake. This study indicated that the distribution range of this species is not currently wide, but it is likely to expand towards the central plateau and southern parts of Iran.