Resistencia a la salinidad en dos especies de peces neotropicales de la familia Cichlidae (Pisces, Perciformes).

GÓMEZ SERGIO E.; GONZALEZ NAYA M. JIMENA

Memoria fundación La Salle de Ciencias Naturales

Fundación La Salle

Año: 2007 p. 45 - 54

0037-8518

  Abstract. Salt tolerance in two neotropical cichlid fish.Fish of the family Cichlidae are restrict to tropical and subtropical freshwater,this species showed certain resistance to salinity and some can tolerate full sea water at least for short time period.This is an empirical generalization with few experimental laboratory data.In this paper the maximum incipient lethal levels (ILL)of salinity were determinated n Cichlasoma biocellatum (35 spms.)and C.facetum (25 spms.),two cichlids with very different geographical distribution.ILL of salinity were determinated using static acute toxicity biossays (96h) under controlled salinity and temperature (24.92 °C)conditions.Measurements were made on groups with f ve specimens,using resistance time technique trying fitness an asymptotic model.The ILL of C.biocellatum was calculated in 26.67 g l-1 and in C.facetum was 20.20 g l-1. Tolerance to high salinity ranges of cichlids,presently restricted to fresh and brackish waters, place them within secondary freshwater species.Considering low salinity values (0.5-10 g l-1) of Neotropical continental waters were they live,their high tolerance to salinity (ILL >20 g l-1) is a character of low or none adaptative value,and should be considered as a physiologic relict from their marine ancestors. Salt tolerance in two neotropical cichlid fish.Fish of the family Cichlidae are restrict to tropical and subtropical freshwater,this species showed certain resistance to salinity and some can tolerate full sea water at least for short time period.This is an empirical generalization with few experimental laboratory data.In this paper the maximum incipient lethal levels (ILL)of salinity were determinated n Cichlasoma biocellatum (35 spms.)and C.facetum (25 spms.),two cichlids with very different geographical distribution.ILL of salinity were determinated using static acute toxicity biossays (96h) under controlled salinity and temperature (24.92 °C)conditions.Measurements were made on groups with f ve specimens,using resistance time technique trying fitness an asymptotic model.The ILL of C.biocellatum was calculated in 26.67 g l-1 and in C.facetum was 20.20 g l-1. Tolerance to high salinity ranges of cichlids,presently restricted to fresh and brackish waters, place them within secondary freshwater species.Considering low salinity values (0.5-10 g l-1) of Neotropical continental waters were they live,their high tolerance to salinity (ILL >20 g l-1) is a character of low or none adaptative value,and should be considered as a physiologic relict from their marine ancestors.