Last month we ran a post from our friend and guest, fisheries biologist Brian Morrison, on Western Alaska Trout Lifecycles. We thought it was super cool when we posted it, and then the comments started pouring in. More than one reader said something like “that was the best post you’ve run, ever”. Our editorial staff might not be that quick, but even so we thought to ourselves “hmmm, maybe it would be cool if we ran more stuff from Brian”.
Good news – today the series continues! We love chasing king salmon in Alaska and Chinook salmon in Canada (it’s a dialect thing, eh), and we were just pleased as punch when Brian sent over his write-up on the science behind these big, badass critters.
Thank you, Brian!
Chinook Salmon Lifecycles
Chinook Salmon (Oncorynchus tshawytscha – pronounced “cha-vee’cha”), also called ‘king’, ‘tyee’, ‘spring’, and ‘quinnat’; are the least abundant of the five Pacific Salmon species, but also the largest. The maximum size ever recorded is 126 pounds caught by a commercial fisherman near Petersburg, Alaska. Unverified reports have noted Chinook that were 150 cm long, and weighed as much as 135 pounds!
The average size across their range is much smaller, with adults being 70-100cm long and 10 to 25 pounds. Chinook will run up short coastal rivers, or large rivers stretching far inland, such as the Yukon River, where adults will travel over 3,000km (2,000 miles) to their spawning grounds. They are also known to travel up streams to over 1,800 meters (6,000 feet) elevation in the Snake River watershed.
Chinook Salmon historically ranged from the Ventura River on the coast of south-central California in the south to Kotzebue Sound in the north. There have also been reports in tributaries of the Arctic Ocean, but these populations may not be self-sustaining. Chinook Salmon have been introduced all across the globe, but have only managed to develop self-sustaining populations in South America, New Zealand, and the Great Lakes.
Chinook Salmon have some of the most diverse life histories of all the Pacific Salmon. There are spring, summer, fall, and winter run populations. All of these life histories will spawn during late summer or the fall, except for the winter run populations, which spawn in the spring. There is only one known population in their native range where this life history is expressed, in the Sacramento River, CA.
Juvenile Chinook Salmon will either smolt out of their spawning tributaries shortly after hatching in the spring (“ocean type smolt”), or spend at least one year, and up to two years in the stream environment prior to smolting (“stream type smolt”). Ocean type smolts are common from fall run adults, while spring and summer run Chinook often produce stream type smolts.
After smolting, Chinook Salmon can spend anywhere from several months to five years in the ocean prior to returning to spawn. Once sexually mature, all adults will die after they spawn, with mature parr surviving to spawn in future years within a controlled setting.
Male salmon have the greatest breadth in spawning age. They are able to successfully spawn as parr (never visiting the ocean), or at any age beyond that. For anglers, it is fairly common to catch ‘jacks’, which spend anywhere from several months to one full year in the ocean. Across their range, Chinook Salmon generally mature at age 3 or 4, and often older at higher latitudes such as Alaska, with individuals as old as age 8 being found.