Physiological parameters of South Georgia Shag (Phalacrocorax georgianus) during breeding in South Orkney Island, Antarctica

Due to climate change and human activities, Antarctic shag populations are experiencing shifts in their distribution range, habitat, and population size. To assess their health, we collected hematological and biochemical of male and female South Georgia shags (Phalacrocorax georgianus) during breeding on Laurie Island, South Orkney Island, Antarctica. Leukocyte profile, heterophil/lymphocyte ratio, hematocrit, and concentrations of glucose, total proteins, cholesterol, and triglycerides were measured. None of the measured metrics showed signs of clinical pathology or disease. Overall, the parameters measured were consistent with those previously reported for other cormorant species. Males had higher protein and cholesterol concentrations, indicating differences in nutritional status between the sexes during reproduction. This study is the first report on blood parameters of South Georgia shags in Antarctica and may be useful for future meta-analyzes comparing blood parameters of different species and geographic areas.