Local and Long Distance Migrations of Maine Atlantic Salmon Smolts: Penobscot Bay to the Scotian Shelf and Beyond

Low marine survival is a challenge to the recovery of Gulf of Maine Atlantic salmon populations, but acoustic tracking studies are helping us to better understand the dynamics of local and oceanic migrations of these fish.  Having tracked more than 1,000 Penobscot River smolts, we have been able to document post-smolt ecology from inner Penobscot Bay into the Gulf of Maine.  Additionally, ocean monitoring has allowed us to track movements in the Gulf of Maine, along the Scotian Shelf using the Ocean Tracking Network’s Halifax Line, and at other coastal Canadian acoustic arrays.  We present a synthesis of postsmolt migration ecology from Maine to these distant locations based on the movement patterns of more than 125 postsmolts.  Our results indicate that many postsmolts transit the Gulf of Maine in less than 45 days.  Potential impacts on the postsmolts from near shore development, fisheries, or changing predator fields within 50 km of the Maine coast likely occur in a very brief timeframe, from 10 May to 5 June.  Our findings also show that postsmolts have variable distribution patterns. The telemetry data have allowed us to identify offshore areas that appear essential for Atlantic salmon postsmolt growth and survival.