Trout can live in saltwater. You can’t take freshwater trout, throw it in the ocean, and expect it to survive, but certain species have anadromous forms. They start their lives in freshwater, go to saltwater conditions to mature, and return to freshwater to spawn.
Fish are some of the most unique animals on earth. Their ability to adapt to different environments and survive harsh conditions is unlike many other animals. Fish like steelhead, salmon, and trout can start their life in freshwater and adapt to saltwater conditions early on.
Trout Living in Saltwater
Generally, trout are sensitive to their water’s saline levels. They need certain conditions to survive, but if they have time to adapt and the proper body composition, they’ll survive in saltwater.
There are two primary genera of trout in the subfamily Salmoninae: euryhaline and stenohaline.
Euryhaline trout are fish that can adapt to different levels of salinity. Anadromous trout fall under the euryhaline category.
Stenohaline trout, however, cannot survive in waters with various saline levels. They are born in the proper conditions and cannot move into water with different saline levels; otherwise, they may die.
If a stenohaline trout moves into higher than normal saline levels, its osmoregulation process is doomed. Freshwater trout constantly drink water and flush it out of their gills. Passing water through their gills helps them breathe, but if they don’t get rid of it, they risk drowning. If a freshwater trout moves into saltwater, the water from its cells leaves, and it dehydrates. Their current cells aren’t able to filter out the salt.
Saltwater trout need to constantly drink water to filter out the salt. They drink more water than freshwater trout because it takes longer to filter the salt from seawater. If you place a saltwater trout directly into pure freshwater, it will over-hydrate itself. The constant water drinking would cause its cells to explode.
Your typical brown, rainbow, brook, cutthroat, and bull trout caught high in mountain streams or lakes are stenohaline trout. They cannot adapt to saltwater conditions.
True saltwater trout species include spotted trout and speckled trout. They cannot adapt to freshwater and only live in saltwater.
Since Euryhaline trout can survive in freshwater and saltwater, their bodies adapt well to different saline levels. Euryhaline trout can drink water to hydrate themselves and excrete water to remove the salt from their cells.
Sea-run rainbow trout (steelhead), sea-run brown trout, and coastal cutthroat are examples of euryhaline trout. They can adapt to saltwater and freshwater.
Brown Trout in Saltwater
Sea-run brown trout live in the Eastern United States and parts of South America. These non-native fish are born in freshwater, move out to saltwater to mature, and return to freshwater to spawn. These sea-run browns are euryhaline fish because they can adapt to freshwater and saltwater.
These anadromous trout take time to adapt to the saline levels. Traveling from the sea into freshwater gives their bodies time to adapt. The saline levels change as they travel further into the freshwater rivers and streams. They don’t move into freshwater in one go. They take their time to take in less and less salt. When they reach their spawning grounds, they’re often in 100% freshwater.
They don’t die after the spawn. Once complete, they’ll venture back into the sea and wait to repeat the process the following year.
Rainbow Trout in Saltwater
Sea-run rainbow trout (steelhead) exist in Western and Eastern North America. Western steelhead swim out of the Pacific Ocean into rivers along the coast and complete the spawn. Like sea-run brown trout, their bodies adapt to the saline levels. They’re likely in 100% freshwater when they’re in their spawning grounds.
The steelhead in the Midwest come from the Great Lakes. The Great Lakes are freshwater, so these steelhead don’t have to adapt to different saline levels. They spend their entire lives in freshwater and are technically stenohaline fish.
Brook Trout in Saltwater
On the East Coast, anglers find sea-run brook trout. These large brook trout have the aggressiveness and tendencies of saltwater fish and can live in saltwater. Like steelhead and sea-run browns, the sea-run brook trout are anadromous. They spend years maturing in saltwater and return to freshwater to spawn.
Coastal Cutthroat Trout
Coastal Cutthroat are some of my favorite fish in the world. These unique fish live on the West Coast of North America. Like the other trout on this list, they’re anadromous. They spend time in saltwater and return to freshwater to spawn.
They can complete the spawn several times in their life. It’s exhausting, but they complete it, return to salt water, and repeat the process. They don’t run as far as salmon. They usually stay within 50 miles of the stream they hatched in.
Frequently Asked Questions
Can Lake Trout Survive in Saltwater?
No, lake trout cannot survive in saltwater. They need to spend their entire lives living in freshwater.
Can Trout Survive in the Ocean?
Yes, trout can survive in the ocean. They’ll survive as long as their bodies can handle a fluctuation of saline levels.
Sea-run trout are a vulnerable fish. A healthy population of sea-run trout proves the ecosystem is flourishing. They need specific conditions to complete their spawn. A sea-run trout’s body can adapt to various conditions but can’t be extreme. They need time for their bodies to adjust to different saline levels to stay healthy. Whether you’re fishing for sea-run brown trout or coastal cutthroat, take the time to appreciate their resilience and beauty.