Watch The Sighting:
This incredible footage was captured by Judy Lehmberg, a wildlife videographer who spends much of her time in Yellowstone National Park. While filming large mammals is often in demand, other keystone species, such as the cutthroat trout, have equally important ecological roles, and their stories can be just as exciting!
A Race Against The Current
Judy’s footage captures the challenging journey of the cutthroat trout as they depart the tranquil waters of Trout Lake and begin their strenuous expedition upstream. She traces their journey as they swim through reeds, struggle through strong currents, and leap over massive rocks.
It is spectacular to watch these fish fight against all odds while making it to their spawning sites. Not only is it an extremely exhausting endeavour, but in shallower areas, they are highly vulnerable to predation from otters, bears, and birds of prey.
To offset the energy expense of spawning, trout use a few different methods to make the journey easier. Firstly, they bulk up on food stores before beginning the migration.
Secondly, as we can see in Judy’s footage, they use the stream currents efficiently by positioning themselves behind rocks, logs, eddies, or other trout to reduce the water’s drag. Finally, they alternate between periods of rest and bursts of movement to recover energy.
One Of Nature’s Incredible Rituals
Spawning behaviour is genetically hardwired into cutthroat trout and can take a few days to a few weeks for each fish. Migration and spawning length depend on the distance from the lake to their chosen tributary, the water depth and speed, and the fish’s physical condition.
Once the trout reach the spawning site, females dig a redd into the loose gravel in areas with clean, oxygen-rich water. Males then compete to court females and release their eggs while the chosen male simultaneously releases sperm.
The redd is then covered to protect the eggs, and the trout will seek deep, calm pools where they can recover slowly with minimal effort. Unlike some species, such as the Pacific Salmon that die directly after spawning, cutthroat trout may return to the lake and survive to spawn in future years, so long as they haven’t completely depleted their energy reserves.
A Delicate Balance
The spring migration of Yellowstone cutthroat trout is more than just a dramatic natural event, it’s vital to the rhythm of a healthy ecosystem. As these trout move upstream to spawn, they stir nutrients from the lake to the stream, feeding not only the waterway but the creatures around it.
Get our Best Sightings as they Come in
The eggs and fry of cutthroat trout become a seasonal food source for species such as osprey and otters. Additionally, other aquatic life benefits from the digging of redds, which stirs the gravel beds and reshapes the stream bottom.
Because they are so sensitive to changes, the presence of thriving spawning populations is a strong sign that the watershed is in good health. When the trout flourish, the ecosystem thrives.
Judy’s footage reminds us that the annual upstream journey of Yellowstone’s cutthroat trout is more than a biological necessity. As these fish push against the current, they show the invisible threads that connect water, wildlife, and wilderness.