The return rate of 2SW adults to Gulf of Maine area rivers by smolt cohort year (1990 – 2017) of hatchery-reared Atlantic salmon smolts (Penobscot River blue triangles), estimated naturally-reared smolt emigration (Narraguagus River dark green dots), and fall parr (Sheepscot River orange squares), (East Machias River light green dots) the USA. Source: USASAC 2020, Kocik.
Smolt to adult return rates (SAR), otherwise known as marine survival, for three different Maine Rivers utilizing four different stocking strategies, are displayed above. This is the estimated number of 2 Sea Winter adults returning to each river calculated through redd and trap counts.
The 60 redds found in the East Machias River in 2019 is the highest observed looking all the way back to 1991 and 6 times the average of the past two decades. The average SAR resulting from the Project (2.117%) is 2 times greater than the previous 5-year average SARs for naturally reared salmon on the Narraguagus River (1.055%) and nearly 20 times greater than return rates of smolt stocked salmon on the Penobscot River (0.107%) (USASAC 2020). To be concise, per capita, the Peter Gray Parr Project method returns more adult salmon than other stocking strategies being used in Maine.
The number of observed Atlantic salmon redds, East Machias River, Maine (1973-2019). Source: Maine DMR – Bruchs
An in-depth Peter Gray Parr Project summary can be found here: Peter Gray Parr Project Summary 2012-2019