shines in the sheltered harbour water

Size
Height: 5–15 cm
Lifespan
2–5 years
Diet
Photosynthetic marine algae. Draws energy from sunlight. Requires clean water stable rock surfaces and good water flow.
Habitat
Grows on rocky reefs and in sheltered harbours throughout New Zealand. From Three Kings Islands down to Stewart Island. Low intertidal and shallow subtidal zones where light filters through water.
Range
Found throughout North and South Islands on rocky reefs and in sheltered harbours. Most common in clear sheltered waters with good water flow. Also found in Australia and South America.
Endemism
Native
Main Threats
None significant. Common and widespread in clear sheltered waters. Localised threats include coastal development pollution sedimentation and climate change affecting temperature.
Population
Not Threatened. Common on rocky reefs throughout New Zealand particularly in sheltered locations with clear water. Often found on vertical rock faces and under overhangs.
Conservation Status
Not Threatened
Human Risk
harmless
Handling Note
marine algae, safe to handle
Conservation Note
Native red algae; not assessed by NZTCS as marine algae are outside the scope of current threat classifications.
Te Ao Māori
No recorded Māori name distinguishes iridescent red algae from other red seaweeds. Likely grouped with other red seaweeds called karengo. Iridescence would have been noticed by Māori. Seaweed that shimmered like scales of fish or surface of sea would have been thing of beauty. Sign of hidden magic of underwater world. Still grows on rocky reefs today. To see shimmer you have to look closely.
Callophyllis variegata is a flat, brownish-red disc clinging to the rock. At first glance it is not flashy. Not bright. Almost drab. But then light hits it at the right angle. It shimmers blue, green, purple, silver. Like oil on a wet road. The iridescence comes from cell structure. Which reflects light to create rainbow effect. Alga of hidden shimmer. Waits for right light to show off. What makes it special is the shimmer. Iridescence is not pigment. It is structural colour. Created by way cell walls bend and reflect light. Same phenomenon that makes soap bubbles shimmer. Peacock feathers glow. Trick of light. Secret hidden in cells. Magic trick that only works when sun is at right angle. Alga of hidden beauty. Keeps best trick for those who look closely. Fronds are flat and fan-shaped. Often split into several broad lobes. Tough and leathery. Able to withstand motion of waves. Edges are wavy and ruffled. Like piece of crinkled paper. Surface is smooth and glossy. Almost waxy to touch. Under water fronds are deep reddish-brown. Almost invisible against rock. Biologically it is red alga. Reproduces by releasing spores from specialised structures on fronds. Spores released into water. Carried by currents. Settle on nearby rocks to grow into new plants. To see iridescent red algae at its best you have to dive beneath surface. In water with light filtering down iridescence is stunning. Fronds shimmer with blue and green. Purple and silver. Subtle show-off. Quiet treasure. Flash of colour in dim light. Alga of patient eye. Rewards those who take time to look. Proves most beautiful things are often hidden in plain sight. No one told it otherwise.