Red Alga Invasive Species Information

What Is Red Alga - (Grateloupia doryphora)?

Habitat: prefers to live in shallow, protected subtidal waters, and likes to attach itself to hard substrates. It can survive water temperatures between 4 and 28° C, and salinities between 12 and 52 parts per thousand. 
Distribution in Ireland: Coastal Areas 

Status: Unknown
Family name: Grateloupia

Reproduction: Spores develop giving rise to filaments and blades.

Red Alga - Grateloupia doryphora

How To Identify Red Alga?

Colour: Red, olive green, brown

Size: The ribbon-like blades of this seaweed can reach a size of 100 cm by 20 cm, but are usually much smaller.

Red alga prefers shallow, protected subtidal waters attaching itself to hard substrates.

Red Alga - Grateloupia doryphora ID Guide

Why Is Red Alga A Problem?

Where Red Aga co-exists, it usually out competes the other non-native species.

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It can invade the habitat of a native seaweed, Chondrus crispus, aka: "Irish Moss", and crowd it out. Irish moss is used commercially to manufacture carigeen, and also provides an important winter food source for local marine invertebrates.

Additionally, the long blades of Red Alga can shade out other local species of algae and prevent them from growing nearby.