Sea lettuce is a type of green algae that belongs to the genus Ulva. It’s found all around the world, along the coasts of oceans.
The Latin name for the most common species of sea lettuce is Ulva lactuca, with “lactuca” meaning lettuce. This group of algae is edible and is also known as Green Nori.
How Does Sea Lettuce Look?
Sea Lettuce has a leaf-like structure called a thallus, which is flat and green in color.
The size of individual blades can grow up to 400 mm (16 inches) when they are in sheltered areas.
These algae attach themselves to rocks or other surfaces using a disc-shaped holdfast.
What Animals Eat Sea Lettuce?
Many different sea animals enjoy eating Sea Lettuce, including:
- Manatees, and
- Sea slugs, also known as sea hares.
Is Sea Lettuce a Food Source for Humans?
Yes, Sea Lettuce is consumed by humans in many countries, such as Scandinavia, Great Britain, Ireland, China, and Japan. In Japan, it is called “aosa.”
People eat Sea Lettuce raw in salads or cook it in soups. It’s rich in protein, soluble dietary fiber, vitamins, and minerals, especially iron.
However, it’s important to be careful about where it’s collected from because some areas may have toxic heavy metals that can make it unsafe to eat.
What Is the Role of Sea Lettuce in The Aquarium Trade?
Sea Lettuce is popular in the saltwater aquarium trade because it has high nutrient uptake and is edible for fish.
Many people who keep reef aquariums use Sea Lettuce in refugia or grow it as food for herbivorous fish.
It’s easy to care for since it can tolerate a wide range of lighting and temperature conditions.
In a refugium, Sea Lettuce can be attached to live rock or another surface, or it can be left to drift in the water.
Are There Any Health Concerns Related to Sea Lettuce?
In 2009, large amounts of Sea Lettuce washed up on the beaches of Brittany, France, and caused a public health scare as it decomposed.
The rotting leaves produced hydrogen sulfide, a toxic gas. There were incidents where people and animals were harmed by the gas.
Environmentalists believe that this problem was caused by excessive nitrogenous compounds from improper disposal of pig and poultry waste from industrial farms.
What Are the Different Species of Sea Lettuce?
There are many different species in the genus Ulva. Some of the accepted species are:
- Ulva acanthophora
- Ulva anandii
- Ulva arasakii
- Ulva atroviridis
- Ulva australis
- Ulva beytensis
- Ulva bifrons
- Ulva brevistipita
- Ulva burmanica
- Ulva californica
There are also some species that are considered “nomina dubia,” or doubtful names, such as Ulva costata, Ulva repens, and Ulva tetragona. New species are also still being discovered.
In 2014, an Indian endemic species called Ulva paschima Bast was identified. Ten new species were discovered in New Caledonia, including Ulva arbuscula, Ulva planiramosa, and Ulva batuffolosa, among others.
Sea Lettuce Characteristics
| Care Level: | Easy |
| Growth Rate: | Fast |
| Nutrient Uptake: | Excellent |
| Required Lighting: | Moderate High |
| Required Water Flow: | Moderate |
| Is Palatable? | Yes |
| Maximum Size: | 8 in (20.3 cm) mound |