Edited sentence: And in fact, several adult alewife were found below the first dam on the river on April 7, 2009.As an analysis revealed they were 3 years old, the assumption of scientists is that these were in fact descendants of the alewife released 3 years before in March 2006.The next step will be to erect fish ladders over the 3 dams lowest on the river, allowing the alewife access to a portion of the river with more suitable spawning habitat