giant spider crab with legs spanning nearly a metre

Size
Length: 50–80 cm, Weight: 1–3 kg
Lifespan
15–25 years
Diet
Carnivorous and scavenging. Feeds on small crustaceans, worms, and carrion. Uses long, spindly legs to walk across seafloor. Scavenges on dead fish and other marine animals. Feeds most actively at night. Climbs onto rocks and kelp to find food.
Habitat
Deep continental slopes and rocky reefs from 50 to 500 metres depth. Prefers cold, clear waters with rocky bottoms. Often found near kelp forests and underwater pinnacles. Uses long legs to climb vertical rock faces and kelp stalks.
Range
Found in deep waters around South Island and subantarctic islands from Cook Strait to Auckland Islands. Most common on Chatham Rise and around Campbell Plateau. Also found in southern Australia. Distribution follows cold deep currents.
Endemism
Native
Main Threats
Bycatch in rock lobster pots and bottom trawls is primary threat. Habitat damage from bottom trawling on rocky reefs poses risk. Climate change affects deep reef habitats. No targeted commercial fishery for this species exists in New Zealand waters.
Population
Population trends poorly understood due to deep-water habitat. Giant spider crab is not targeted commercially in New Zealand. Caught occasionally as bycatch in rock lobster pots and trawl fisheries. Long, spindly legs make it difficult to handle. No formal stock assessment exists.
Conservation Status
Not Threatened
Eighty centimetres from claw tip to claw tip. That is the span of its legs. It is the first thing anyone notices. The body itself is relatively small. Perhaps fifteen to twenty centimetres across. But the legs keep going. Spindly and jointed. They make the crab look like something designed by someone who started with a normal crab and then kept adding length. Proportion is skewed. Scale is deceptive. Hooked hairs cover those long legs. The hairs collect algae and debris. This provides camouflage against the rocky bottom. When the crab stands still on a kelp-covered reef, it is almost invisible. The legs blend with the seaweed. The body disappears into the shadows. Only movement gives it away. Stillness is survival. Motion is risk. Cold, clear water defines its world. The giant spider crab lives on deep continental slopes and rocky reefs. Depth ranges from fifty to five hundred metres. It inhabits waters around the South Island and the subantarctic islands. It prefers temperatures that would kill most other crabs. The water is dark. It is under high pressure. It is rich with life. Kelp forests grow on the rocky reefs. The crab climbs the stalks. It searches for food. Adaptation is specific. Tolerance is narrow. Slow and deliberate, it moves across the seafloor. The long legs are built for climbing and stability. Not for speed. Each leg moves in sequence. A mechanical gait seems almost robotic. When disturbed, the crab raises its claws. It spreads its legs. It makes itself look as large and threatening as possible. The threat is largely for show. The claws are not powerful enough to crush shells. The crab is not aggressive. Bluff is the strategy. Violence is not an option. Scavenging is its primary occupation. The giant spider crab eats dead fish, small crustaceans, and worms. It does not chase its prey. It waits. Or it wanders. It eats what it finds. At night, it climbs onto rocks and kelp stalks. It searches for food above the seafloor. By day, it hides in crevices. It stays safe from the large fish that patrol the reef. Night is for feeding. Day is for hiding. Moulting is a slow, dangerous process. The crab sheds its old exoskeleton. It inflates a new, soft one. Because it is so large and lives in deep water, we rarely see the empty shells. They are eaten by scavengers. Or broken down by currents. The crab grows slowly. It lives for a long time. Perhaps fifteen to twenty-five years. This is a slow pace of life. It is common in cold, deep-water species. Time moves differently here. No one targets it. The giant spider crab has no commercial value. It is caught occasionally as bycatch in rock lobster pots and bottom trawls. But it is not considered a valuable catch. Its long, spindly legs make it difficult to handle. Its meat is not prized. For most people, it is a curiosity. A photograph from a deep-sea submersible. A specimen in a museum jar. Value is subjective. Utility is low. On the deep reefs off the South Island, it is alive. It climbs the rocks in the dark. It scavenges. It moults. It reproduces. It has been doing this for millions of years. Long before humans ever sailed these waters. The giant spider crab does not know it is strange. It just is. No one told it otherwise.