Test Your Habitat IQ



The Penobscot River is New England’s second largest river, draining nearly one-third of the State of Maine with a watershed area of 8,570 square miles. The Penobscot River is used as a spawning or nursery area by 11 migratory fish species, including three listed under the Endangered Species Act. The river hosts the largest run of Atlantic salmon left in the United States. Historically, fisheries on the Penobscot River were bountiful, with an estimated 14 to 20 million alewives, 75,000 to 100,000 Atlantic salmon, and 3 to 5 million American shad. 

The Penobscot River watershed has a rich cultural history of commercial, recreational and sustenance fishing.  It is home to the Penobscot Indian Nation, who still occupies part of their ancestral homeland on Indian Island, surrounded by Penobscot waters.



Over the centuries, human activities have caused adverse impacts to the watershed. Dams, culverts, water pollution and overfishing contributed to an almost complete elimination of many sea-run, migratory, fish species and their habitat. With fewer alewife and blueback herring, important commercial species like cod and other fish, birds and mammals have lost a key food source. This also has affected tribal sustenance fishing and the historically large recreational fishery for Atlantic salmon.  

Degraded water quality has led to a loss of bottom-dwelling communities, restrictions on fish consumption, and overgrowth of algae.  All of this has diminished the watershed’s ability to recover from the effects of climate change, such as warming water temperatures and potentially increasing flood magnitudes and frequencies.




NOAA will now develop an implementation plan for the Penobscot River watershed.


Please email any questions to Matthew Bernier at Matthew.Bernier@noaa.gov.