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In order to prevent the extinction of the species, scientists have been monitoring the endangered Chinook salmon which lives in the Alaska’s Bristol Bay region.
By placing a tracker using atom isotopes in their ear bones, scientists studied and collected data about where they are born and the areas where they swim in the first year of life.
This in turn offers experts answers about what they need in their natural environment, in order to recreate it accurately for protection and prevention from extinction.
Back in 2011, researchers from the University of American state Fairbanks where the ones to capture and study specimens from Alaska’s Bristol Bay region; soon after that, a curious chemical signature found on the salmon’s ear bones (also called “otoliths”) attracted their attention.
Just as a tree has its rings, scientists discovered that these ear bones also store information throughout a fish’s life, adding new layers with new data. By studying the otoliths, they found information about the place where the fish lived, and they cross-referenced the chemical signatures of its otolith with the water’s in which it swims in.
Scientists were surprised to see that signatures did not disappear when the fish moved to new waters; instead, they just kept adding one on top of the other, in clean layers. Each new growth ring faithfully represents how the waters were in which the fish was swimming at the time.
According to lead author Sean Brennan, postdoctoral researcher at the University of Washington’s School of Aquatic and Fishery Sciences, each fish has its own “little recorder,” which stores the entire life history of the fish.
Each migration was carefully stored in the fish’s ear bone – so much so that each stream it swam in, from hatching to adulthood, was recorded.
Co-author Matthew Wooller, head of the Alaska Stable Isotope Facility at University of Alaska Fairbanks, explained that data gathered from the otolith could be vital in forming a better understanding of why the Chinook salmon’s population is in constant decline.
Moreover, scientists could even pinpoint if it’s overfishing, climate change or industrial development that causes specific groups of salmons to become extinct. Experts can study environments that seem favorable to their reproduction, and see their reaction when it is harmful to them.
Co-author Christian Zimmerman, ecologist at the U.S. Geological Survey, strongly believes that mapping salmon productivity is one of the best ways science can respond to their needs and the effects on ultimate number of salmon.
Image Source: TIME
