Why was bass reproductive success chosen as a criterion?

The St. Croix River was blocked to the alewife due to concerns that increasing numbers of alewife in the early-mid 1980s played a role in the rapid decline in young-of-year (YOY) bass – those one year old or less -- in Spednic Lake around the same time. Although the evidence of the alleged past interference is inconclusive, a precautionary approach to alewife restoration would guard against the possibility of negative impact on the bass.