Etruscan chub (Squalius lucumonis)
Mohamed bin Zayed Species project number 192521809
Concret conservation actions for the Etruscan chub Squalius lucumonis and the Italian nase Protochondrostoma genei in central Italy
The main aim of the project is to improve the status of S. lucumonis and P. genei populations, in terms of abundance and age structure, within their respective original ranges: the Tiber River basin (Tyrrhenian side of the Italian peninsula) for S. lucumonis, and the Esino River basin (Adriatic side) for P. genei.
Both target fish species of the project are endemic to Italy. Specifically, the Etruscan chub is endemic to the Tuscany Latium Ichthyogeographic district, with a natural range limited to only three river basins in Central Italy: Ombrone, Arno, and Tiber (Giannetto et al., 2013; Kottelat & Freyhof, 2007). The Italian nase is endemic to the Padano-venetian district; its native range extends in Adriatic basins, from Soca (Isonzo) river basin to the Vomano River (Kottelat & Freyhof, 2007). For S. lucumonis a decreasing population trend has been reported (IUCN, 2019). For this reason the species is listed as endangered in the International Union for Conservation of Nature (IUCN) Red List of threatened species (IUCN, 2019), and it is listed as species in critical risk of extinction (CR) in the IUCN Red List of Italian vertebrates (Rondini et al., 2013). The progressive reduction of the species range is due to habitat alterations and water withdrawals (Kottelat & Freyhof, 2007); in recent years alien fish species invasions represent an additional threat. Even for the South European nase, in recent decades the distribution pattern of the species within its native areal has become fragmented, due to the alteration of habitat, the deterioration of water quality (Gandolfi et al., 1991), and of the introduction of alien species (Crivelli, 1996); moreover, the species is of recreational interest for sport fishermen. For this reason the species is listed as Least Concern (LC) in the International Union for Conservation of Nature (IUCN) red list of threatened species (IUCN, 2019) and it is listed as endangered (EN) in the IUCN red list of Italian vertebrates (Rondini et al., 2013).
Both species were originally allopatric, but in the 60s P. genei was unintentionally translocated from Northern Italy to the Tiber River basin; since then, P. genei was often in co-presence with the Etruscan chub, with which can compete causing negative effects to disadvantage of the native species.
In favour of the Etruscan chub recovery and conservation, the project proposes the removal of alien species (including P. genei) with which competition phenomena for food and habitat can arise, and the decrease in fishing pressure. In particular, the concrete conservation actions foreseen by the project involves: i) the alien fish species removal in 2 sites within the Tiber River basin; ii) except for P. genei, the disposal of the removed species; iii) the transfer of P. genei coming from the Tiber river basin to the native Esino River basin, with the aim to improve the populations status in this area where the species is reported in decline (Lorenzoni et al., 2011); iv) restocking activities in favour of S. lucumonis, using selected populations in good conservation status as a source to collect wild specimens. The removal of P. genei has the dual function of improving the population status of the Etruscan chub and the possibility of having wild P. genei specimens to be reintroduced into their original range (Esino River basin).