Chum salmon was unfamiliar in Arctic waters, such as the Interior Alaska river systems. In a recent discovery, researchers have confirmed that this fish species reproduces farther north in some North Slope rivers.
Ominous Sign of Ecosystem Transformation
Salmons wander the ocean before returning to the rivers where they hatched. Their life cycle requires them to fire themselves upstream to spawn and then drop dead. This system allows species such as chum salmon to find new habitats, with some seeking out different rivers where they spawn.
Over the last few decades, native fishing communities along the North Slope of Alaska have reported catching chum salmon, but they are finding more recently. In September, experts confirmed the discovery of around 100 chum salmon in the Itkillik and Anaktuvuk rivers.
Evolutionary ecologist Peter Westley from the University of Alaska, Fairbanks, reported that they saw fish that were not only actively spawning or just finished spawning and were still alive but also fish that had been spawning and already died. This discovery is consistent with the clear harbinger of climate change involving the shift toward the poles.
The researchers assume that the chum salmon strayed north at some point instead of returning to spawn in their home rivers. Higher rates of straying are observed in warmer years. As salmon take advantage of newly suitable habitat, the Arctic rivers may become suitable for them.
Scientists have just begun to study the ecological consequences of the arrival of chum salmon to these new territories. They may interact with the native fish species the residents have long relied on. Although the new populations are small, they could compete with native fish for space and resources, altering the system's ecology. The North Slope community members also worry that if the number of chum salmon grows substantially, they might attract a new commercial fishing industry.
On the other hand, the chum salmon may also help native fish by providing food for them with the eggs they laid in the rivers. Since the frigid Arctic waters are not particularly productive, there is not a tremendous amount for native species like Arctic char and Dolly Varden to eat. When the Dolly Varden and resident fish populations can eat salmon spawn, some of their eggs fail to get buried.
Ecological Impacts of Climate Change
Scientists suggest that the spawning of chum salmon in the Arctic could signify rapid climate change. The Arctic region warms up to four times faster than the rest. More species migrate to higher altitudes because the Arctic becomes more hospitable to them, while their native habitat becomes less so. The region is also greening as shrubs and trees get a foothold in the new climate.
Increased warming of the Arctic creates more liquid water. This water can come from permafrost degradation, which, when thawed, can allow for the connection between the surface rivers and the groundwater springs. Melting glaciers also provide new rivers for the salmon to spawn in.
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