King Salmon (Oncorhynchus tshawytscha), often called Chinook salmon, are highly valued for their size and are a prized catch for sport fishers. They are known for their impressive dimensions.
Understanding King Salmon Size
King salmon are the largest of the Pacific salmon species. Adults typically weigh between 30 and 80 pounds, although some can exceed 50 pounds. Their lengths generally range from 30 to 40 inches, with some individuals reaching over 50 inches. The size of a King salmon often correlates with its age and the duration it spends in the ocean; they can live up to seven years, and the longer they feed, the larger they grow. For instance, a two-year-old mature fish might weigh less than 4 pounds, while a seven-year-old fish can easily exceed 50 pounds.
King salmon spend anywhere from one to six years feeding in the ocean before returning to their freshwater spawning grounds. The average time spent in the ocean is typically three to four years.
Record-Setting King Salmon
The largest King salmon ever officially recorded by an individual angler was a 97-pound, 4-ounce fish caught by Les Anderson in Alaska’s Kenai River in 1985. This record-setting Chinook was nearly five feet long and had a girth of 37.5 inches. It remains the world record for sport-caught King salmon.
In commercial fishing, an even larger King salmon was caught. A 126-pound specimen was harvested in a fish trap near Petersburg, Alaska, in 1949. While not caught by rod and reel, this historical catch highlights the potential maximum size these fish can attain. These exceptionally large King salmon are typically found in the waters of Alaska, particularly in rivers like the Kenai, which is renowned for producing massive Chinook.
What Influences Their Growth?
Several factors contribute to the size of King salmon. Genetics play a role, as some fish are predisposed to larger sizes and longer lifespans.
The availability and quality of food are also crucial for growth. In their ocean feeding grounds, King salmon are predators, consuming a variety of prey such as herring, anchovies, squid, and other small fish. Abundant and nutrient-rich food sources directly influence their growth rates and maximum size.
Ocean conditions, including water temperature and currents, affect both the King salmon themselves and their food sources. Warm ocean temperatures can lead to fewer planktonic organisms, which are essential for the prey of juvenile salmon. These conditions can also increase the presence of warm-water predators, posing a threat to growing salmon.
The amount of time a King salmon spends at sea is directly related to its size. Fish that spend more years feeding in the ocean generally grow larger before returning to spawn. Some King salmon may spend one to eight years in the ocean, with older fish often being the largest. Additionally, the distance of their spawning run can influence their size; fish that travel shorter distances to their natal rivers may conserve more energy, which could otherwise be used for growth. However, extreme weather events like heavy rainfall and high water temperatures in freshwater habitats can negatively affect egg survival and overall productivity.