Following the decline of otter population during almost all the last century, the animal has gradually left the Northern an Central regions until it was declared extinct in Abruzzi in 1982. After this date no signs of presence was recorded for almost twenty years. It was only in the firsts years of the 2000 that the otter returned to swim in the Sangro River.
Above, the Sangro basin state in 2004, with just one spot testifying the presence of the species.
The Lontrack project was born in 2010 with the intent to investigate the otter population status at the Northern limit of the expansion from the South. In 2012 we surveyed again the entire Sangro basin which resulted almost completely occupied.
During three years, the research showed that the Sangro and the Aventino River — his main tributary — host a stable population of 14 otters, eight males, four females, and two individuals of which we were unable to ascertain the sex, divided in four family clusters.
Along the 122 Km span between the spring and the estuary in the Adriatic Sea, the Sangro river is blocked by several dams. The most important two are the Barrea Dam and the Bomba Dam, which create upstream a reservoir with the same name.
The two dams have different shapes and they appear to have different impacts on the aquatic species. While Lake Bomba has hosted, at various times, at least five otters (from two family clusters) we were unable to find any signs of presence upstream the Barrea Dam despite our best sampling efforts.
In conclusion, 14 otters share the Sangro River along the 64 Km between the Barrea Dam and the confluence with the Aventino River. They can be sorted in four family clusters as illustrated below.