fans out on the sunlit reef rocks

Size
Height: 10–20 cm
Lifespan
2–5 years
Diet
Photosynthetic marine algae. Draws energy from sunlight in clear, sheltered waters. Requires clean water and stable rock surfaces.
Habitat
Grows on rocky reefs throughout New Zealand from Three Kings Islands to Stewart Island. Low intertidal and shallow subtidal zones. Clear water and sun-dappled reefs.
Range
Found throughout North and South Islands on rocky reefs in low intertidal and shallow subtidal zones. Most common on North Island east coast and South Island northern coast. Also found in Australia and South America.
Endemism
Endemic
Main Threats
None significant. Common and widespread in clear, sheltered waters. Localised threats include coastal development, pollution, sedimentation, and climate change.
Population
Not Threatened. Common on rocky reefs throughout New Zealand. Particularly in clear, sheltered waters. Often grows on vertical rock faces and under overhangs.
Conservation Status
Not Threatened
Human Risk
harmless
Handling Note
marine algae, safe to handle
Conservation Note
Endemic brown algae; not assessed by NZTCS as marine algae are outside the scope of current threat classifications.
Te Ao Māori
No recorded Māori name distinguishes fan weed from other brown seaweeds. It was likely grouped with other brown seaweeds called rimu. The fan-shaped fronds would have been noticed. They looked like the fans used by chiefs. Like the spreading fingers of a hand. Like the rays of the sun on the water. The fan weed was sometimes used as decoration. Stiff, leathery fronds were gathered and dried. Then used as fans or woven into garlands.
Zonaria turneriana looks like a hand fan. A seaweed that is a deck of cards. The fronds are flattened, broad, and fan-shaped. A semicircle of golden-brown tissue. Sometimes split into several lobes. The surface is marked with concentric bands of darker and lighter tissue. Like the growth rings of a tree. Or the layers of a deck of cards. It is stiff and leathery. It holds its shape in the current. Refusing to be bent by the flow of water. A seaweed that is stiff. What makes it special is the layering. The fan weed grows in overlapping tiers. One frond above another. Like a stack of fans. The fronds are attached to the rock by a small, disc-like holdfast. They branch repeatedly. Creating a dense, layered canopy. It is the deck of cards of the underwater world. A city of golden-brown layers. The fan weed is a brown alga. A member of the Dictyotaceae family. It reproduces by releasing spores from specialised structures on the surface of its fronds. The spores are produced in dark spots. Visible on the surface of the fan. Tiny dots that mark the sites of reproduction. The fan weed provides habitat for small invertebrates. Tiny crustaceans hide among its fronds. Small snails graze on its surface. Its layered structure creates a complex, three-dimensional habitat. A city of small spaces. A refuge for the small and the vulnerable. To find fan weed is to find a golden-brown fan on the rock. The rocky reef is underwater. The fan weed grows in overlapping tiers. Golden-brown, stiff and leathery. Bands of light and dark. A tiny crustacean hides among its fronds. The fan weed does not know it is a city. It does not know it is a deck of cards. It just wants to hold its shape in the current. The layered one. The fan-shaped one. The one that proves that the sea loves geometry as much as the land. The fan weed is proof. It carries on regardless of the tide. This becomes expensive for those who wish to dredge the reefs. The numbers are not encouraging for extraction. The plant adapts faster than expected. It waits for nothing. It just exists in the surge. A quiet presence in a noisy ocean. No one told it otherwise.