walks through the kelp forest

Size
Carapace: 10–15 cm, Leg span: 40–60 cm
Lifespan
5–8 years
Diet
Omnivorous. Eats kelp, sponges, and small invertebrates. Steady grazer.
Habitat
Kelp forests and rocky reefs in shallow to moderate depths. Structured reef.
Range
Throughout New Zealand. From Three Kings Islands to Stewart Island.
Endemism
Endemic
Main Threats
Kelp harvesting and habitat loss. Increased predation when exposed.
Population
Common in coastal reefs. Cold-tolerant and widespread distribution.
Conservation Status
data_deficient
Human Risk
caution
Handling Note
long legs and spiny carapace can cause minor scratches
Conservation Note
Marine crustacean outside the scope of current NZTCS terrestrial and freshwater assessments.
Te Ao Māori
Spider crabs are often encountered by divers and rock pool explorers. Their strange, elongated forms evoke a sense of alien architecture. In Māori tradition, large crabs were valued as food, though specific references to this species are not distinct from other large crustaceans.
In 1853, H. Milne-Edwards described this species from specimens collected in New Zealand waters. It was named after the French naturalist Hombron's companion, Gaimard. The name sticks. The crab remains. It is a large, long-legged inhabitant of the kelp forest. Threats are localised. Kelp harvesting removes its primary habitat. The crab relies on kelp for camouflage and food. Without the forest, it is exposed. Predation increases. Survival decreases. Diet is omnivorous. It eats kelp, sponges, and small invertebrates. It uses its chelae to clip and tear. It is not a fast eater. It grazes steadily. It contributes to the turnover of plant matter. Range covers the entire coastline of New Zealand. It is found from the Three Kings Islands to Stewart Island. The water temperature varies. The crab adapts. It is cold-tolerant. It thrives in the south. Habitat is structured reef. It needs vertical surfaces for climbing and hiding. Flat sand is avoided. The crab is clumsy on open ground. In the kelp, it is agile. It moves among the fronds. It disappears.