In the South
Sea lettuce is often found washed ashore in great green carpet-like masses at the high tide level.
It grows prolifically in estuaries and harbours and can be a real nuisance in a variety of ways.
This photograph shows a single sea lettuce plant growing naturally in a clear rocky shore pool.
Sea lettuce is a native plant and is described as a green algae which normally grows in sheets that are two cells thick. Each plant can grow to a length of around 30 cm.
It's rich in vitamins A and B and when harvested from clean habitats it's a good food, especially when used in salads. It can be eaten raw or cooked.
When conditions such as a period of warm weather coincides with an increased nutrient supply the result can be what's described as an algae bloom. At such times, sea lettuce can grow at an alarming rate and block waterways and pollute beaches. Rotting sea lettuce has a very unpleasant smell and in summer this odour can result in many complains from seaside residents.
There is, however, another side to the sea lettuce story.
It's already being used as a garden mulch and as a fertiliser and an expert in aquaculture believes that in the future it could be farmed and turned into biofuel.
What's now to many just a smelly nuisance could one day be providing fuel for international flights.
Sea lettuce is an under-rated, prolific native plant.
- © Fairfax NZ News