| Abstract [eng] |
Among marine mammals in the Baltic Sea, grey seals (Halichoerus grypus) are the most widespread species and are considered important indicators of ecosystem health due to their top position in the food chain. Increasing attention is being paid to the developmental period of pups, especially to the interaction between endocrine and immune factors, in the context of environmental pollution and hormonal imbalance. The aim of this Master's thesis is to assess the changes in estradiol concentrations—a steroid hormone—and their association with hematological and morphometric parameters during the early development of grey seal pups. The objectives of the study are: (1) to determine estradiol concentra-tions using different ELISA kits; (2) to compare the effect of sample extraction on hormone quantifi-cation; (3) to evaluate blood parameters using both manual and automated counting methods; and (4) to assess the relationship between estradiol levels, leukocyte counts, and developmental stages. The study compares different estradiol measurement methods, evaluates leukocyte composition, and ana-lyzes their association with body mass, sex, and developmental stage. The results revealed significant relationships between leukocyte variation and estradiol concentration during development, contribu-ting to a better understanding of pup physiology and the effects of environmental factors on Baltic grey seal populations. . |
