#salmon rivers

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Salmon Jungle by Paul Vecsei Via Flickr: One of several salmon streams in the Bella Coola Valley. It's not every stream that has the right mix of current velocity and substrate size required by spawning salmon. Few fish were using this site while I was there. Nikon D700 FX Nikon AF Zoom-Nikkor 20-35mm f/2.8 D Lens set at 20mm 400 ASA

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Century-old salmon-smeared notebooks reveal past bounty of fisheries

DNA analysis of scales stuck to page suggest wild sockeye declines in Canada have been larger than thought

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.

Until now. This week, scientists unveiled a study that makes clever use of the fish DNA preserved in the battered, smeared books to reconstruct how wild Skeena salmon have fared over the past century. The conclusion is sobering: Declines have been more precipitous and widespread than previously understood, with the river’s 13 major wild sockeye salmon populations plummeting by 56% to 99% over the period from 1913 to 2014, largely because of overfishing.

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What happened to the populations of animals that depended on the salmon?