Tinca tinca has the potential for moderate environmental impact if introduced to the Great Lakes.
Tench have been found to act as a vector for parasites in their introduced range. In a sample of tench from the Richelieu River, 9 of 10 carried parasites. One parasite in particular, Valipora campylancristota, may pose a threat to the native copper redhorse (Moxostoma hubbsi; Marcogliese et al. 2009). Other parasites and diseases tench have been found to carry include a fish tapeworm (Ligula intestinalis; Aydogan et al. 2018), a myxosporeans (Thelohanellus pyriformis; Goswami et al. 2022), and carp edema virus (Matras et al. 2019). Tench may also harm native cyprinids and other benthic species through competition (Avlijaš et al. 2018).
Experimental trials showed that tench negatively impact gastropod populations, indirectly leading to increased periphyton biomass and alter physical habitat by reducing macrophyte abundance through trophic cascades (Beklioglu and Moss 1998, Avlijaš et al. 2018). Additionally, the presence of tench is predicted to disturb sediment, reduce water clarity, and disrupt trophic cascades, further affecting macrophytes and promoting epiphytic algae in the Great Lakes region (Avlijaš et al. 2018).
There is little or no evidence to support that Tinca tinca has the potential for significant Socio-Economic impacts if introduced to the Great Lakes.
Tench are not reported to pose any threat to human health, damage infrastructure, affect water quality, harm economic sectors, or inhibit recreational activity.
Tinca tinca has the potential for moderate beneficial impacts if introduced to the Great Lakes.
Tench were originally brought to the United States for use as a food and sport fish (USFWS ERSS 2014). Tench may be mixed with other rough fish for sale (Avlijaš et al. 2018). However, there is not much demand for tench, and their economic contribution is insignificant (Dumont et al. 2002, Marcogliese et al. 2009). Tench are sometimes fished recreationally, however there are already numerous sport fish established in the Great Lakes.