International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.4, 153-162 http://ecoevopublisher.com/index.php/ijmec 15 5 discovered in the United States many times. Among them, the breeding population was first confirmed in a pond in Maryland in 2002. Since then, northern black fish have successfully colonized in basins such as the Potomac River in the middle Atlantic of the United States and spread to adjacent water systems (Wegleitner et al., 2016; Odenkirk and Isel, 2016). In Europe, there were only sporadic records in the past: for instance, a giant black fish was caught in the hot spring waters of Tuscany, Italy in 2012, and northern black fish were introduced to Slovakia and the Czech Republic in the 20th century but did not form sustained populations (Piazzini et al., 2014). Figure 1 Map of sampling sites for C. argus. The red dot shows the specific sampling locations (Adopted from Liu et al., 2024) In other parts of Asia, the spread of black fish is more manifested as artificial transplantation beyond their original distribution areas. For instance, in China, the northern black fish was once introduced as a farmed species into some waters in the south, resulting in competition between it and the spotted black fish (Channa maculata), which is native to South China. Red-scaled black fish were introduced into reservoirs in Malaysia and proliferated explosively (Simberloff and Vitule, 2014). Reports in the Middle East show traces of invasive black fish found in wetlands in Iran and Iraq, speculated to be caused by aquatic release. In Africa, Madagascar introduced striped black fish from Asia for aquaculture in the 1970s. Later, they escaped into natural water bodies due to floods and spread, affecting the local freshwater fish population. 2.3 The role of human activities in diffusion Human activities are one of the main driving forces for black fish species to break through geographical barriers and achieve transcontinental diffusion (Harrington et al., 2022). The introduction of species in aquaculture is an important way for the large-scale transfer of black fish. The black fish has delicious meat and grows rapidly. It is a popular edible fish in some countries in East and Southeast Asia, and in some regions, it is also believed to have medicinal and nourishing value. Therefore, people have made many attempts to introduce black fish into new areas for aquaculture or restocking fisheries. For instance, in the 1960s, the Soviet Union introduced northern black fish for fishery resources and conducted experiments on stocking them in waters outside the Far East.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==