Concentrations of some metals were determined in muscle tissue of five marine fish species (Engraulis encrasicolus, Sarda sarda, Mullus barbatus, Trachurus mediterraneus, and Merlangius merlangus) caught from the Eastern Black Sea coast of Turkey in 2017. Heavy metals were analyzed by using inductively coupled plasma-optical emission spectrometry after the muscle tissues of fish were digested by acids. The metal accumulation differences between species were investigated statistically. The levels of aluminum, cadmium, chromium, copper, iron, manganese, lead, and zinc in the muscles of fish were 3.27, 0.12, 0.27, 2.04, 9.97, 1.00, 0.95, and 10.65 µg/g, respectively. The highest levels of aluminum, cadmium, chromium, and manganese were detected in E. encrasicolus; the highest levels of lead and zinc were accumulated in T. mediterraneus and the highest concentration of iron and copper was found in S. sarda. The average lead concentration values were found to be above the limit values determined by national and international standards due to anthropogenic inputs such as mining activities and agricultural wastes. In addition, potential risks associated with human consumption were evaluated using quality indices such as estimated daily intake and target hazard ratio. According to these indexes, a potential risk in terms of human health has not been identified due to consuming fish tissues.

Biological invasions are increasingly recognised as a major global change that erodes ecosystems, societal well-being, and economies. However, comprehensive analyses of their economic ramifications are missing for most national economies, despite rapidly escalating costs globally. Türkiye is highly vulnerable to biological invasions owing to its extensive transport network and trade connections as well as its unique transcontinental position at the interface of Europe and Asia. This study presents the first analysis of the reported economic costs caused by biological invasions in Türkiye. The InvaCost database which compiles invasive non-native species' monetary costs was used, complemented with cost searches specific to Türkiye, to describe the spatial and taxonomic attributes of costly invasive non-native species, the types of costs, and their temporal trends. The total economic cost attributed to invasive non-native species in Türkiye (from 202 cost reporting documents) amounted to US$ 4.1 billion from 1960 to 2022. However, cost data were only available for 87 out of 872 (10%) non-native species known for Türkiye. Costs were biased towards a few hyper-costly non-native taxa, such as jellyfish, stink bugs, and locusts. Among impacted sectors, agriculture bore the highest total cost, reaching US$ 2.85 billion, followed by the fishery sector with a total cost of US$ 1.20 billion. Management (i.e., control and eradication) costs were, against expectations, substantially higher than reported damage costs (US$ 2.89 billion vs. US$ 28.4 million). Yearly costs incurred by non-native species rose exponentially over time, reaching US$ 504 million per year in 2020-2022 and are predicted to increase further in the next 10 years. A large deficit of cost records compared to other countries was also shown, suggesting a larger monetary underestimate than is typically observed. These findings underscore the need for improved cost recording as well as preventative management strategies to reduce future post-invasion management costs and help inform decisions to manage the economic burdens posed by invasive non-native species. These insights further emphasise the crucial role of standardised data in accurately estimating the costs associated with invasive non-native species for prioritisation and communication purposes.