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  • Writer's pictureHaley

Atlantic Salmon in Hot Water

Updated: Jan 16, 2023

Endangered wild Atlantic salmon have no shortage of challenges to face as they brave the wild to survive not only in the Atlantic Ocean, but also in Maine’s own rivers. Between deadbeat dams that block fish passage, predation by larger fish, and man-made pollution impacting water quality, Atlantic salmon have no easy feat making it upstream to their spawning grounds to breed!

Our main goal at Downeast Salmon Federation (DSF) is to give Atlantic salmon the best possible chance they have to repopulate their natural habitat here in Maine, the last hold out for the endangered fish in the United States. We do this by protecting Maine rivers through advocacy and conservation work, as well as rearing our own Atlantic salmon in our hatcheries located along the Pleasant and East Machias Rivers. We have released nearly 1.5 million endangered Atlantic salmon into Maine rivers since 2012. This has boosted the species’ probability of proliferating out in the wild, but even that isn’t foolproof, as the fight against extinction starts from day one for our salmon.

While it has been documented that global ocean temperatures are rising, it isn’t only salt water bodies that face these repercussions of climate change. River temperatures have been on the rise here as well and just like lobsters adapting by migrating north in the ocean, our salmon will have to overcome the stress associated with warmer water.

Atlantic salmon ideally prefer cool river water between 15 - 18 degrees C, a little bit cooler than room temperature. At the Peter Gray Hatchery, we pull water directly from the rivers these hatchery-raised salmon will be released into. This summer, we have observed water temperatures as high as 26 degrees Celsius, a whopping 10 degrees higher than what salmon prefer.

There are ways around exposing salmon to this extreme heat in the hatchery setting. Many hatcheries’ main source of water comes from springs or water from deep pools in rivers and lakes. Others that lack access to cool water may implement systems that can cool the water.

Our hope is that salmon reared in the same warm river water that they will be stocked into will be better adapted to survival in the wild, when they inevitably face natural stressors out in Maine’s river systems.

A hot July day on one of Maine's more exposed rivers

There are ways that we can combat rising river temperatures in Maine. One of our main pillars of conservation at DSF is protecting riparian ecosystems – that includes not only the rivers, but the land that surrounds them. When we establish properties as DSF conservation easements, we hope to preserve the land in its natural state, limiting human intervention like building and logging that can result in lower quality habitat for Atlantic salmon and other sea-run fish. Cutting down trees adjacent to rivers results in a loss of canopies, meaning the sun projects directly to the water and heats things up.

Cool, clean rivers cooled by canopies of abundant forests is what our salmon need, and what we are dedicated to protecting and conserving here in Downeast Maine.

Well shaded river with a healthy canopy

If you’d like to get involved, please get in touch with us to learn more about our conservation efforts, and opportunities to volunteer with our land trust!

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