The Eutrophication Status of Aquaculture Areas in the Black Sea (Sinop) Using TRIX, UNTRIX, and TQRTRIX Indices

Eutrophication, resulting from the environmental impacts of aquaculture activities and the presence of excess nutrients, is particularly significant for aquatic ecosystems. The present study aims to evaluate the eutrophication and trophic status of an aquaculture zone along the southern coast of the Black Sea by employing various indices and comparing the findings with established threshold levels for coastal waters. Water quality parameters-including chlorophyll-a, dissolved oxygen, dissolved inorganic nitrogen, and total phosphorus-were measured at 16 aquaculture production sites located along the southern Black Sea coast. Based on these measurements, TRIX, UNTRIX, and TQRTRIX values were calculated. The average temperature at the production sites was determined to be 21.72±0.11°C (p>0.05), the average salinity was ‰16.84±0.05 (p>0.05), the average pH was 8.28±0.03 (p>0.05), and the average dissolved oxygen concentration was 8.69±0.06 mg/L (p<0.05). The TRIX, UNTRIX, and TQRTRIX values ranged from 2.48 to 4.17, 1.48 to 3.51, and 0.31 to 0.88, respectively. When the water quality parameters and index values from the sampling stations were compared with reference thresholds, variations in trophic status were observed among the sites.