strings out in the gentle bay mudflats
- Size
- Length: 20–50 cm
- Lifespan
- 2–5 years
- Diet
- Photosynthetic. Grows in sheltered bays and estuaries. Requires clean water, stable mud or sand substrates, and slow currents.
- Habitat
- Sheltered bays and estuaries in low intertidal and shallow subtidal zones. Grows on mudflats and sand flats where waves are gentle.
- Range
- Found throughout the North and South Islands in sheltered bays and estuaries. Common in low intertidal and shallow subtidal zones.
- Endemism
- Native
- Main Threats
- None significant. Localised threats include coastal development, pollution, and climate change affecting water temperature.
- Population
- Not Threatened. Common in sheltered bays and estuaries throughout New Zealand, often growing in large beds on mudflats and sand flats.
- Conservation Status
- Not Threatened
- Human Risk
- harmless
- Handling Note
- marine algae, safe to handle
- Conservation Note
- Native 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 the string kelp from other brown seaweeds. It was likely grouped with other brown seaweeds called rimu. The long, rope-like strands were sometimes used as cordage. They could be twisted and braided into lines, though they were not as strong as fibres from other plants. The string kelp beds were recognised as places of shelter. Small fish hid among the strands. The long, trailing ropes created a forest of green in shallow water.
It has no fronds. Chorda filum has no branches. No floats. It is a single, long, thin, rope-like tube. Hollow and filled with air. It can grow up to three metres long. But only a few millimetres thick. It looks like a piece of green string. Or a thin drinking straw. Minimal design. Maximum length. A seaweed that does not waste energy.
What makes it special is the simplicity. String kelp has stripped away everything unnecessary. No complex structures. No branching fronds. No specialised parts. Just a long, hollow tube anchored to the mud by a small, disc-like holdfast. The seaweed equivalent of a minimalist sculpture. A design that raises questions. The answers are in the current.
Flexible and strong, it bends in the current. It trails behind like a long, green tail. It can twist and tangle without breaking. Surprisingly tough for something so thin. A seaweed that does not break.
Reproduction happens by releasing spores from specialised structures on its single, tube-like body. Spores are released into the water. Carried by currents. They settle on nearby mudflats to grow into new plants. String kelp provides habitat for small invertebrates. Tiny crustaceans hide among its strands. Small fish shelter in the tangled beds.
To find string kelp is to find a tangle of green ropes in shallow water. Trailing in the current. Swaying back and forth.
The current is slow. The string kelp trails. Long and green. Bending but not breaking. It does not need to be complex. It does not need to be flashy. It just needs to hold on. And it does.
No recorded Māori name distinguishes the string kelp from other brown seaweeds. It was likely grouped with other brown seaweeds called rimu. The long, rope-like strands were sometimes used as cordage. They could be twisted and braided into lines. Though they were not as strong as fibres from other plants. The string kelp beds were recognised as places of shelter. Small fish hid among the strands. The long, trailing ropes created a forest of green in shallow water. Today the string kelp still grows in sheltered bays of New Zealand. Visible at low tide as a tangle of green ropes in shallow water. The minimalist. The simple one. The one that proves length is its own kind of beauty.