Study of Dimensional and Morphological Characteristics of Erythrocytes in Some Black Sea Fish of Different Evolution Position and Ecological Specialization

Abstract

A comparative analysis of the morphometric parameters of erythrocytes in two species of cartilage (Chondrichthyes) and five species of teleosts (Teleostei) Black Sea fish of different natural mobility was carried out. The volume, area, and shape index of the cell and nucleus, the specific surface and useful volume of the cell, and the nuclear-cytoplasmic ratio are calculated based on the linear dimensions of the cell and the nucleus. It has been shown that the studied cartilaginous fish (rays) had larger erythrocytes compared with the teleosts: the linear dimensions are 2–3 times larger, and the volume is 7–30 times larger. In actively swimming teleosts, the volume of erythrocytes and their nuclei is smaller than those of slow-moving species (2–3 times and 5–9 times, respectively). The revealed differences in the erythrocytes’ morphometric characteristics of cartilaginous and teleosts are considered to reflect the direction of the evolutionary process towards increasing the energy potential of the circulatory system of the “younger” fast-swimming teleosts.