Analysis of mineral and heavy metals in fish otoliths in theTigris River, Turkey

Abstract

Rising pollution levels pose significant threats to fisheries. By analyzing the different components of fish body structures, we can better understand the interactions that occur in response to environmental changes. Otoliths are structures in the inner ears of fish and record the environmental changes to which they are exposed throughout their lives. Recent studies have shown that fish otoliths provide information on the accumulation of minerals and heavy metals in the environment. The accumulation of minerals and heavy metals in fish otoliths can be an important indicator for understanding environmental interactions and, ultimately, assessing the sustainability of fishery resources. In this study, 62 samples of Acanthobrama marmid, Alburnus mossulensis, Paracapoeta trutta, Capoeta umbla, Carassius gibelio, Chondrostoma regium, Cyprinion kais, Cyprinion macrostomum, Luciobarbus mystaceus and Planiliza abu were obtained from fishers in the Tigris River. The presence of Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn was analyzed by inductively coupled plasma optical emission spectrometry (ICP-OES) in the otoliths. The average levels of heavy metal residues in the otoliths were determined as Co>Cr>Cu>Fe>Mn>Ni>Pb and Zn. The minerals Ca, K, Mg, Na and P were found to be statistically significant among fish species (P<0.05). According to the Tukey HSD multiple comparison test, the highest values of Ca, K, and Na were found in P. abu and of Mg in C. gibelio . The data can be used as a reference for the assessment of mineral and heavy metal accumulation in fish otoliths in terms of fishery management and environmental protection, and can be compared with data from studies of different fisheries.