The weight of a salmon varies tremendously across species and life stages. Salmon weight is not uniform, ranging from a few pounds in the smallest species to well over 50 pounds in the largest. The species of salmon is the most significant factor determining its weight, with the smallest mature adults being over 20 times lighter than the largest individuals.
Species-Specific Weight Ranges
The Pacific salmon species exhibit the widest range of average weights, reflecting their different life strategies. Chinook salmon, commonly known as King salmon, are the heaviest, with mature adults typically weighing between 15 and 30 pounds. Large Chinook often exceed 50 pounds, making them the largest of all salmon species.
Chum salmon (Dog salmon) generally range from 8 to 15 pounds, though some can reach over 30 pounds. Coho salmon (Silver salmon) are slightly smaller and more consistent in size, with most adults falling between 7 and 12 pounds. Sockeye salmon average 6 to 9 pounds, with a weight range of 5 to 15 pounds.
The smallest and most numerous species is the Pink salmon (Humpback salmon), which rarely weighs more than 5 pounds, averaging 3.5 to 5 pounds. Wild Atlantic salmon, while a different genus, average around 10 pounds.
Biological Drivers of Weight Variation
Differences in weight among species are primarily driven by their life histories, particularly age and diet. Chinook salmon spend up to five years in the ocean before spawning, allowing for a much longer growth period compared to Pink salmon, which mature and return in only two years. This difference in longevity is a determinant of maximum size.
Dietary habits also play a significant role in determining final adult weight. Chinook salmon are nekton feeders, preying on fish like herring and squid, which supports substantial growth. Smaller species like Pink and Sockeye salmon are primarily zooplankton feeders, consuming tiny organisms that offer less energy density for rapid growth.
A salmon’s weight changes dramatically during the spawning migration. Once an adult enters freshwater, it stops feeding and relies entirely on stored energy reserves. This demanding migration can cause a significant loss of body mass, with Atlantic salmon losing approximately 50% of their body weight by the time they finish spawning.
Market Standards and Record Catches
The heaviest salmon ever recorded was a Chinook salmon caught near Petersburg, Alaska, in 1949, weighing 126 pounds. The official sport-caught world record for Chinook stands at 97 pounds and 4 ounces, caught in Alaska’s Kenai River in 1985. These exceptional weights represent the maximum growth potential of the species.
The size of salmon most consumers encounter is far more modest, dictated by commercial farming and processing standards. The majority of salmon sold globally, particularly Atlantic salmon, is farm-raised and harvested at a consistent market size, typically between 8 and 10 pounds (3.6 to 4.5 kilograms).
When purchased as fillets, a single portion usually ranges from 4 to 6 ounces, or larger fillets are sold in the 2 to 3-pound range. This weight uniformity reflects a focus on efficiency, where fish are grown to a profitable size in about two years before processing.