Biological aspects of Amazonian fishes--VI. Hemoglobins and whole blood properties of Semaprochilodus species (Prochilodontidae) at two phases of migration.

Electrophoretic patterns of hemoglobins, red blood cell phosphates, Bohr effect of blood and stripped hemoglobin, ATP and GTP modulation of Hb-O2 affinity of two species belonging to the genus Semaprochilodus (S. insignis and S. taeniurus--jaraquis), captured at two different locations in Rio Negro, near Manaus (Amazonas), are described. High Bohr effect values were found in these two species and in jaraqui-açu (a possible hybrid between them). In S. insignis a higher Bohr effect for migrating individuals was observed, while S. taeniurus showed the reverse. The main erythrocytic phosphates found in these two species are ATP and GTP. They have a large influence on the O2-Hb binding properties in both species. The GTP/ATP ratio showed large differences between catching places. The two species have different electrophoretic patterns. Semaprochilodus insignis showed four anodal components which showed quantitative variation between catching places; S. taeniurus had three anodal components and a similar quantitative variation.