Moving Salmon
Before salmon eggs hatch into alevin, the first mobile stage of the salmon life cycle, the eggs can be moved and transported into different waterways than the one in which the egg was spawned. Due to the delicate nature of salmon eggs, this transfer must take place once the developing salmon's eye is visible within the egg. If eggs are moved at this point, after the salmon embryos have visible eyes, the vast majority of the salmon that hatch will migrate to the water they were moved to. [3]
This trait has been exploited in salmon aquaculture in the development of new hatcheries, and rejuvenating struggling or depleted wild runs, and has been known about since the early 1900s, when some sockeye salmon (Oncorhynchus nerka) were moved from Yes Lake, OR, to the Columbia River, in hopes of adding fish to the declining runs. [4]
Despite large historical records of this trait being present in Pacific salmon, the precise reason for why moving salmon at this stage can change migration pattern is still not completely understood. This, however, does suggest that exposure to certain environmental conditions plays a large role in the ability for individual salmon to find their natal stream. More research is needed in discovering precisely what these factors may be.
Despite large historical records of this trait being present in Pacific salmon, the precise reason for why moving salmon at this stage can change migration pattern is still not completely understood. This, however, does suggest that exposure to certain environmental conditions plays a large role in the ability for individual salmon to find their natal stream. More research is needed in discovering precisely what these factors may be.
The general salmon life cycle, here additionally marked with the relative salinity of the water each state takes place in. The stage in which eggs can be transported is during the incubation phase, before emergence as alevin. Photo credit: United States Forest Service