Evaluation of haematological and biochemical stress biomarkers and physiological parameters in Carassius gibelio caught in the coastal zone of the Curonian lagoon

This study aimed to assess the health status of Carassius gibelio, a comparatively tolerant fish species, in the largest coastal lagoon in Europe – the Curonian Lagoon. Haematocrit and glucose levels were evaluated as reliable biomarkers of stress responses in fish. Additionally, non-specific physiological biomarkers, including hepatosomatic index and condition factor, were utilized to assess the environmental quality of the Curonian Lagoon. Fish samples were collected from two sites: the southern part of Klaipėda port, known as Kiaulės Nugara Island, and the central part of the Curonian Lagoon near Ventė Cape. Based on the multi-biomarker responses of C. gibelio, differences were observed between the two sampling sites, but not statistically significant. Consequently, C. gibelio cannot be recommended as a suitable bioindicator of environmental pollution and is not recommended for biomonitoring surveys of the Curonian Lagoon.