August 20, 2019 — One day in June 1919, workers in a busy Canadian cannery in Port Essington rushed to clean, cook, and can the bright red flesh of a huge number of sockeye salmon hauled from the nearby Skeena River. Watching the frenzy was a government “fisheries overseer” named Robert Gibson. Periodically, Gibson selected a fish, scraped off a few scales, and affixed them to the pages of a small notebook using the salmon’s own slime. Next to each sample—he collected a total of 125 on this day—Gibson wrote the weight, length, sex, and catch date. A U.S. fish biologist hired by British Columbia would follow up by calculating each fish’s age with the then-new technique of using a microscope to count the growth rings visible on the scales, much as botanists age a tree.
Over more than 3 decades, from 1912 to 1948, Gibson and colleagues filled dozens of notebooks with fish scales from the Skeena, Canada’s second-largest salmon river. Ultimately, however, the records were dumped in a box and largely forgotten.