ORIGINAL ARTICLE

Effect of Artificial Light on Physiological and Hematological Parameters of Individuals of Phoxinus phoxinus (Linnaeus, 1758)

In the natural environment, the life activity of organisms takes place under conditions of stable daily, lunar and annual light cycles. However, human activities aimed at creating comfortable conditions for people have resulted in light becoming one of the factors of anthropogenic environmental pollution. Artificial lighting at night can cause physiological and behavioural changes and disturbances in aquatic organisms, affecting their vital functions. Fish are one of the groups of aquatic organisms that are most susceptible to the influence of light at night, largely due to the anatomical structure of their eyes. The aim of this work was to test whether keeping Phoxinus phoxinus (Linnaeus, 1758) under constant light exposure promotes the growth of inflammatory processes in them, and also to study whether lighting at night affects oxygen consumption. Experiments showed that the oxygen consumption of P. phoxinus increased statistically significantly (p = 0.04303) at night with light compared to night without light. In an experiment in which blood cell counts were performed, the results showed a statistically significant increase in leukocytes (p = 0.01506) in the third experimental group of four kept under constant artificial light for 17 days. Based on the results of our study, it has been confirmed that keeping fish under abnormal light conditions, i.e. using different sources of artificial light at night near water bodies, can lead to physiological changes that can have a negative impact on the life of organisms. In fish, the level of oxygen consumption increases, indicating an increase in the level of metabolism, which in turn affects the growth and formation of organisms, causing a decrease in the intensity of various physiological processes such as feeding and reproduction. There is also an increase in the level of leukocytes, which indicates an increase in inflammatory processes in the organisms, which can lead to a decrease in immune function and, as a result, the susceptibility of fish to various diseases.