King crabs are marine crustaceans known for their impressive size. Inhabiting cold, deep waters, their substantial dimensions are notable. Their considerable size highlights unique adaptations within marine ecosystems.
The Giants Among Crabs
The Red King Crab (Paralithodes camtschaticus) stands out as the largest among king crab species. A mature male Red King Crab can achieve a maximum weight of 24 pounds (10.9 kg). These crustaceans can also have a leg span of up to 5 feet (1.5 meters). Their carapace, the shell covering their back, can measure up to 11 inches (28 cm) in width.
While females are also large, they typically do not reach the same maximum dimensions as males, with female Red King Crabs weighing up to 10.5 pounds. The average male Red King Crab caught in the Bering Sea weighs around 6.4 pounds (2.9 kg).
Diverse Species, Varying Sizes
The term “king crab” encompasses several distinct species, each possessing its own typical and maximum size ranges. The Red King Crab is generally the largest. Its substantial size makes it a prominent species in commercial fisheries.
The Blue King Crab (Paralithodes platypus) is another species, capable of growing to a considerable size. While generally smaller than the red king crab, blue king crabs can weigh up to 18 pounds (8.2 kg) and have a leg span approaching 6 feet (1.8 meters). Their average weight is around 6 pounds.
The Golden King Crab (Lithodes aequispinus), also known as the Brown King Crab, is the smallest of the commercially harvested king crab species. These crabs weigh between 5 and 8 pounds (2.3 to 3.6 kg).
What Fuels Their Growth
King crabs achieve their notable sizes due to biological processes and environmental conditions. Their habitats, often in the cold, nutrient-rich waters of the North Pacific and Bering Sea, provide abundant food resources. These waters, ranging from 3.2 to 5.5 °C, support a diverse ecosystem that supplies their omnivorous diet of invertebrates, fish parts, and organic matter.
A long lifespan also contributes to their growth, allowing them time to accumulate mass. Red and Blue King Crabs can live for 20 to 30 years, providing many molting cycles for size increases.
Crabs, like all crustaceans, possess a rigid external skeleton, or exoskeleton, which does not expand. To grow, king crabs must undergo molting, shedding their old shell. A new, soft shell forms underneath, which the crab inflates by absorbing water to increase its body size before it hardens. While juveniles molt frequently, this process becomes less frequent as they mature, but each molt allows for a significant increase in size.