Application of pectoral fin spine of starry sturgeon fish as an indicator of the habitat evaluation in the Caspian Sea

Although the use of indicator organisms and their different tissues is commonly used to evaluate environmental pollution, there is still a need to identify a non-lethal, reliable and sensitive indicator in aquatic environments. In this research, multivariate indices were used based on habitat accumulation conditions. For this purpose, the ratio of elements of pectoral fin spines of ozone-exposed fish were compared as a non-lethal index to evaluate the habitat of the north and south of the Caspian Sea. For this purpose, multivariate analyzes and non-normal analyzes were used in the required cases to compare the samples of North and South Caspian Sea. The ratios of W: Ca, Tl: Ca, Ta: Ca, Sn: Ca, Se: Ca, Ni: Ca, Nb: Ca were higher in the southern samples than in the northern ones, which probably reflected the difference in the availability of metal absorption compared to calcium. Despite the recorded differences in the proportion of pectoral fin spine elements of ozone-exposed fish between the north and south of the Caspian Sea, all the multivariate results also reflected this habitat differentiation. These results showed that the pectoral fin spine can be confirmed as a good non-lethal indicator due to its capacity to accumulate pollutants and also as a biological indicator, and therefore it can be used for environmental evaluations, although the importance of continuous monitoring and protective measures is suggested along with continuous evaluations.