Salmon have a remarkable and unique life cycle that takes them between both freshwater and saltwater environments This leads many people to ask is salmon a freshwater fish or a saltwater fish? The answer is not so simple Let’s take a closer look at the life stages of salmon to understand their relationship with freshwater and saltwater habitats.
Salmon Begin Life in Freshwater
All salmon species begin their life cycle hatching in freshwater streams rivers or lakes. After hatching from their eggs in gravel riverbeds, the baby salmon are called alevins. The alevins stay in the freshwater environment until their yolk sac is fully absorbed and they develop into juvenile salmon called fry.
At this stage, the juvenile salmon feed and grow in their natal freshwater streams and rivers from anywhere between a few hours to several years, depending on the species. Some common lengths of the freshwater residency period include:
- Chinook salmon: Up to 5 months
- Coho salmon: Up to 1 year
- Pink salmon: Often just a few days
- Sockeye salmon: 1 to 4 years
- Atlantic salmon: 2 to 3 years
So while the length of time varies, all salmon are born in freshwater and spend their early life stages in rivers, streams or lakes.
Most Salmon Migrate to Saltwater as Juveniles
Once the juvenile salmon reach a certain age and size, they undergo a fascinating physiological transformation that allows them to survive in saltwater. This process, called smoltification, prepares them for the migration out to the ocean.
During smoltification, salmon develop increased salinity tolerance, change their body chemistry, alter their metabolism and go through physical changes in color and shape. After going through this transformation, the juveniles are known as smolts.
At this stage, smolts will migrate downstream and out to the ocean. Their bodies are now primed to transition into the saltwater environment, where they will spend the next phase of life.
In the ocean, salmon continue to grow and mature. Most salmon species will spend between 1 to 5 years feeding and swimming in the rich, cold waters of the North Pacific and North Atlantic oceans before returning to freshwater to spawn.
Mature Salmon Return to Freshwater to Spawn
When the salmon reach sexual maturity after their time at sea, they begin an incredible journey back to the freshwater streams and rivers where they were born.
Using their keen sense of smell, salmon migrate sometimes thousands of miles to locate their exact natal stream or river. Driven by this homing instinct, the salmon stop feeding during migration and use up all their energy reserves to battle upstream and reach their destination.
Once back in the freshwater rivers and streams, the salmon will spawn. Spawning behavior and timing varies amongst species, but in general the female salmon lays her eggs in gravel nests called redds, the males fertilize the eggs, and the adult salmon eventually die after spawning.
The eggs will hatch into alevins and the salmon life cycle begins anew.
Some Salmon Live Entirely in Freshwater
While anadromous salmon migrate between fresh and saltwater, some populations spend their entire life in freshwater. These are known as landlocked salmon.
Landlocked salmon most commonly occur when a natural barrier like a waterfall or human-made obstruction like a dam prevents access to the ocean. Without the ability to migrate out to sea, landlocked salmon complete their lifecycle entirely in freshwater lakes and rivers.
Researching Atlantic Salmon in Maine Image
Salmon migrating upstream through a fish passage. Credit: NOAA Northeast Fisheries Science Center
For salmon in Maine, most current research focuses on two priorities – the impact of dams on populations and survival of salmon in the ocean.
Atlantic salmon may be facing new challenges in the Gulf of Maine due to changing environmental conditions. Increasing numbers of hatchery-raised Atlantic salmon smolts are entering the ocean via the Gulf of Maine, but fewer are returning to spawn, raising questions as to what is happening to these fish at sea. A 2011 study co-authored by a NOAA Northeast Fisheries Science Center researcher suggests that changing spring wind patterns, warming sea surface temperatures, and new predators along altered migration routes are affecting the survival of Atlantic salmon.
NOAA and USDA launched the Alternative Feeds Initiative in 2007 to identify alternative ingredients to fishmeal and fish oil in aquaculture feeds. NOAAs Northwest Fisheries Science Center Aquaculture Program has been investigating production and use of alternative feed ingredients, processing fish waste, determination of nutrient requirements, and alternative lipid sources.
The National Ocean Service’s CAPP Program assesses aquaculture environmental interactions and develops spatial planning and eco forecasting tools.
NOAA works with academic partners and fishermen in New Hampshire to grow steelhead trout using Integrated Multi-Trophic Aquaculture, which allows multiple marine species to grow at the same time within and around a single structure. Net pens of steelhead trout are surrounded by blue mussels and sugar kelp, which absorb nitrogen waste released by the trout, resulting in a net removal of nutrients from the water column.
Species in the Spotlight Priority Actions
The Species in the Spotlight 2021–2025 Priority Action Plan for the Gulf of Maine DPS builds on the ESA recovery plan and the 2016–2020 Priority Action Plan and details the focused efforts that are needed over the next five years. These actions are:
- Reconnect the Gulf of Maine with headwater streams.
- Improve habitat productivity to increase the number of salmon smolts entering the ocean.
- Increase understanding of and ability to improve marine survival.
In the first five years of Species in the Spotlight initiative (2016-2020), NOAA Fisheries and our partners took important steps toward stabilizing this species and preventing its further decline. Our accomplishments included activities in several areas:
Releasing a tagged salmon.
- Worked with dam owners to make dams safer for migrating salmon.
- Five new fishways planned at hydro dams since 2015.
- 70 aquatic connectivity projects completed in 2018–2019.
- Improved access to approximately 250 miles of streams and rivers.
- Improvements at road crossing provide for more resilient infrastructure during flooding
- Negotiated 15 metric ton catch reduction at West Greenland for 2018–2020, as well as an improved licensing and catch monitoring program.
- Continued work with the North Atlantic Salmon Conservation Organization.
- Satellite tag project to better understand ocean habitat use and migratory patterns.
The Salmon’s Life Mission | Destination WILD
FAQ
FAQ
Is salmon a freshwater or sea fish?
Salmon are typically anadromous: they hatch in the shallow gravel beds of freshwater headstreams and spend their juvenile years in rivers, lakes and freshwater wetlands, migrate to the ocean as adults and live like sea fish, then return to their freshwater birthplace to reproduce.
Are salmon farmed in fresh or saltwater?
Salmon farming involves raising salmon throughout its lifecycle, which takes around three years. The first year of production takes place in controlled freshwater environments, and then the farmed salmon are transported to seawater where they stay through to harvest.
Can salmon be born in saltwater?
Salmon are anadromous.
This means they start their lives in freshwater, migrate to the ocean where they grow, then return home to their natal, or birth, streams to spawn and die.
Is pink salmon a freshwater fish?
Pink salmon are anadromous – they hatch in freshwater streams and rivers then migrate out to the saltwater environment of the ocean to feed and grow. Unlike coho, Chinook, or sockeye salmon, pink salmon do not reside in fresh water for an extended period.
Are salmon freshwater or saltwater?
As such, salmon are one of few species that are both freshwater and saltwater fish. Keep reading this article if you want to learn more about the fascinating life cycle of the salmon, including how they look and taste in fresh and saltwater and what landlocked salmon are.
What is a freshwater fish called?
Sometimes the terminology used for the freshwater forms of saltwater fish is confusing. Atlantic salmon that exist in freshwater lakes without access to the sea are popularly called landlocked salmon or landlocked Atlantic salmon to distinguish them from the saltwater version. Some folks may refer to them simply as freshwater salmon.
Do Atlantic salmon live in freshwater or saltwater?
The answer to this question is both yes and no. As mentioned earlier, Atlantic salmon are anadromous fish that live in both freshwater and saltwater environments during their life cycle. They spawn (lay eggs) in freshwater streams before migrating to the ocean to mature.
Where do salmon live?
Salmon spend most of their life cycle in saltwater environments, but they also inhabit freshwater habitats. Here’s a breakdown of their habitats: Freshwater: Salmon are born and raised in freshwater rivers, streams, and lakes. They spend about 1-3 years in freshwater before migrating to the ocean.
Is salmon a cold water fish?
Salmon (Salmo salar) is a species of fish that belongs to the family Salmonidae. It is a cold-water fish that is native to the northern hemisphere, primarily found in the Pacific and Atlantic Oceans. Life Cycle of Salmon Salmon are anadromous fish, which means they migrate from the ocean to freshwater to spawn.
How do freshwater salmon live?
For example, landlocked freshwater salmon will make their way from the freshwater river or stream where they’re born to the deeper waters of a lake. There, they try to mimic the lives they’d live in the ocean. In contrast, saltwater salmon move to the ocean to live their adult lives until they reach sexual maturity.