The shortnose sturgeon is currently both state (MA) and federally listed as an endangered species. Since the original listing, substantial information about the shortnose sturgeon population of the Connecticut River has been obtained, leading to periodic scrutiny of the endangered listing. In the Connecticut River, shortnose sturgeon appeared to be divided into two populations: one landlocked between Turners Falls and Holyoke Dam, and the other below Holyoke Dam to Long Island Sound.
Between 1980 and 2012, 133 shortnose sturgeon have been lifted at the Holyoke Dam. While hundreds of individuals were identified below the dam from 1993-1995, only between one and six were passed in any one of these years. In 1996, a record number of sixteen-shortnose sturgeon passed above the Holyoke Dam (Kynard 1998).
Recent unpublished work indicates there may be more interaction between these two populations then previously believed. Estimates of total adult abundance calculated in the early 1980's range from 297 to 516 above Holyoke Dam and around 800 in the downstream population. More recent tagging studies have indicated that populations in the lower river have increased to as many as 1,000 individuals (Savoy 2005).