Feeding of Two Cichlidae Species (Perciformes) In an Hypertrophic Urban Lake

Feeding of Two Cichlidae Species (Perciformes) In an Hypertrophic Urban Lake

Alejandro Yafe, Marcelo Loureiro, Flavio Scasso, and Federico Quintans.

Abstract:

Diet of two cichlid species, Cichlasoma facetum (Jenyns, 1842), and Gymnogeophagus rhabdotus
Hensel, 1870, was studied in Rodó Lake, an urban hypertrophic lake in Uruguay. The stomach contentsfrom 192 individuals of C. facetum and 202 of Gg. rhabdotus, obtained through seasonal sampling in the year 2000, were analyzed. The occurrence frequency and the alimentary importance index of each food item were calculated for each season and size class in both species. Cichlasoma facetum fed upon insects (mainly chironomid larvae and pupae), fish (Cnesterodon decemmaculatus Jenyns, 1842), and vegetals (algae, periphyton and macrophytes debris); large individuals also fed upon the freshwater shrimp Palaemonetes argentinus Nobili, 1901. Gymnogeophagus rhabdotus consumed zooplankton (mainly copepods), vegetals (algae and detritus) and Chironomidae larvae in a lesser extent.

Link to full article: http://www.scielo.br/pdf/isz/v92n4/a09v92n4.pdf

Dicordance In Chromosome Number Among Somatic and Gonadal Tissue of Geophagus Balzanii

Dicordance In Chromosome Number Among Somatic and Gonadal Tissue of Geophagus Balzanii (Pisces: Cichlidae).

Eliana Feldberg and Luiz Antonio Carlos Bertollo

Abstract:

Gymnogeophagus balzanii (Pisces: Cichlidae) is characterized by the fact that its somatic cells (kidneys and gills) exhibit 2n = 48 chromosomes. Analysis of testis cells not only revealed the occurrence of the expected haploid number equal to 24, but also showed the presence of a few extra chromosomes. As a viable hypothesis, we propose that these are supernumerary chromosomes which are absent in the somatic cells analyzed.

Link to full article: http://web2.sbg.org.br/gmb/edicoesanteriores/v07n4/pdf/a04v07n4.pdf