King crabs are marine crustaceans known for their substantial size. They typically inhabit the cold, deep waters of the North Pacific Ocean, where conditions support their growth. This article explores the sizes of common king crab species, factors influencing their growth, and how they are measured.
Common King Crab Species and Their Typical Sizes
Among the various types of king crabs, the Red King Crab, Blue King Crab, and Golden King Crab are particularly well-known for their size and commercial value. The Red King Crab (Paralithodes camtschaticus) is generally the largest, with males reaching a carapace width of up to 28 cm (11 inches) and a leg span of 1.8 meters (5.9 feet). These crabs can weigh up to 12.7 kg (28 pounds), though average commercially landed males in the Bering Sea weigh around 2.9 kg (6.4 pounds) with a carapace width of approximately 17 cm (7 inches).
Blue King Crabs (Paralithodes platypus) are also substantial in size, with mature males typically weighing between 2.7 to 3.6 kg (6 to 8 pounds). Some individuals, particularly from the Pribilof Islands, have been known to exceed 8 kg (18 pounds). While often smaller in weight than red king crabs, blue king crabs can exhibit a leg span of up to 1.8 meters (6 feet).
Golden King Crabs (Lithodes aequispinus), also known as Brown King Crabs, are generally the smallest of these three commercially important species. Their average weight ranges from 2.3 to 3.6 kg (5 to 8 pounds). Golden King Crabs typically have a leg span of about 0.91 meters (3 feet), which is noticeably shorter than their larger relatives.
Factors Affecting King Crab Growth
The size of king crabs results from a combination of biological characteristics and environmental conditions. They possess a long lifespan, often 20 to 30 years, which allows for slow, gradual growth.
Growth in king crabs, like all crustaceans, occurs through molting, where they shed their rigid exoskeleton to expand in size. While juveniles molt frequently, this process becomes less common as they mature. Cold, nutrient-rich waters, such as those found in the North Pacific, contribute to their large size by providing a stable environment and abundant food sources. Their diet, which includes a wide range of organisms like worms, clams, mussels, and other invertebrates, provides the necessary nutrients to accumulate significant mass over time.
Exceptional Sizes and Measurement
King crabs can reach exceptional sizes. The largest Red King Crab on record was a male caught in the Bering Sea in 1977, weighing 12.7 kg (28 pounds) and boasting a leg span of 1.5 meters (5 feet). Another account describes a male red king crab with a carapace width of 47 cm (18.5 inches).
The size of king crabs is commonly measured using several metrics, including overall weight, leg span, and carapace width. Leg span is typically measured from the tip of one leg to the tip of the opposing leg. Carapace width refers to the measurement across the widest part of the crab’s main body shell. In commercial contexts, king crab legs are often graded by the number of legs required to make a 4.5 kg (10-pound) package, providing a practical way to categorize their size for market.