Gracilaria parvispora, also called Long Ogo, Red Ogo, or simply Ogo, is a large species of marine red alga.
It’s native to Hawaii and is popular for being a tasty edible seaweed. People in Hawaii also call it Limu Ogo.
What Does Ogo Look Like?
Shape and Size
Ogo has pointed, cylinder-shaped branches that are 1 to 4 mm in diameter.
These branches grow from a central axis, which is 0.8 to 3.5 mm in diameter. The alga can grow up to 60 cm (23.6 in) long.
The color of Ogo can change based on factors like sunlight, water flow, and depth.
While it’s generally red, it can also be yellow, brown, green, white, and black.
Where Is Ogo Found?
Ogo is mostly found in Hawaii, especially around the islands of Oahu and Molokai. Some specific places where it grows include Kane’ohe Bay, Ke’ehi Lagoon, One’ula Beach, and ‘Ewa Beach.
It’s also found at Hau’ula, Coconut Island, and the Oceanic Institute of Hawaii Pacific University.
Presence in Baja California Sur
Ogo has been introduced to Baja California Sur, a region in Mexico. It has been found in places like San Ignacio Lagoon, San Buto, San Juan de la Costa, and La Concha Beach.
However, the extent of its impact on native biodiversity in this region is not well-known.
What Are the Ideal Conditions for Ogo?
Ogo thrives in nutrient-rich water, moderate to high lighting and current, and specific water conditions like:
- dKH between 8 and 12,
- pH between 8.1 and 8.4,
- Water salinity between 1.010 and 1.025 SG,
- Water temperature between 71.6–82.4 °F (22–28 °C),
- Calcium between 390 and 440 ppm,
- Magnesium between 1200 and 1400 ppm,
- Phosphate between 0.01 and 0.1 ppm, and
- Nitrate between 1 to 20 ppm.
How Fast Does Ogo Grow?
Under ideal conditions, Ogo can grow very quickly. It can increase its biomass by 150% or more in just one month.
It’s one of the fastest-growing species of Gracilaria and is one of the larger species of red algae native to Hawaii.
Why Is Ogo Important?
Edible and Cultural Significance
In Hawaii, Ogo is one of the most popular edible seaweeds. It’s used in a variety of dishes, like poke, or eaten raw.
People from different cultures, like Hawaiian, Korean, Filipino, Japanese, and Caucasian, use it in their recipes.
Conservation and Overharvesting
Ogo has become rare in the wild due to overharvesting.
In 1988, a law was passed to protect it by banning the collection of fertile Ogo, which has cystocarps.
Researchers have studied ways to grow Ogo in controlled environments, like floating baskets or submerged lines.
Growing it in these ways can help protect wild populations from overharvesting.
Ogo is a nutritious food source for fish and invertebrates.
In aquariums, it can be used as food for herbivorous fish like tangs, rabbitfish, pygmy angelfish, and blennies.
Use in Aquariums
Ogo is a popular and hardy macroalga for use in marine aquariums. It can be grown attached to substrate or left unattached to help remove detritus.
It’s often used in refugia for nutrient export, as a hitching post for seahorses, or for display.
Gracilaria parvispora Characteristics
|Required Lighting:||Moderate High|
|Required Water Flow:||Moderate High|
|Is Palatable?||Not really|
|Maximum Size:||10 in (25.4 cm)|