Comparative Hematology of Lepomis microlophus and Cichlasoma cyanoguttatum

sunfish, Lepomis microlophus (Centrarchidae), and the Rio Grande perch, Cichlasoma cyanoguttatum (Cichlidae), from Hidalgo County, Texas, was studied from October 1974 to December 1975. There were no significant differences between the sexes in either species, but both species exhibited significant variation in blood parameters due to differences in standard length, reproductive condition or season. Change in reproductive condition apparently affected erythrocyte size. Seasonal changes in hemoglobin concentration and erythrocyte dimensions of L. microlophus were consistent with a pattern of increasing values with increasing water temperature. Erythrocyte size in C. cyanoguttatum may decrease with increasing water temperature. Hemoglobin concentration of the two species was similar, but L. microlophus had a larger number of erythrocytes and less hemoglobin per erythrocyte than C. cyanoguttatum. Comparative data suggest that the magnitude of difference in the hematology of L. microlophus and C. cyanoguttatum is no greater than that which exists between species of Lepomis.