Green, brown and red macroalgae
A diverse macroalgal community grows on the rocky reef and sand within the Cook Island Aquatic Reserve, with depth and wave activity influencing where species can attach and grow.
Macroalgae come in a wide range of colours and varieties, from red articulate coralline algae like Galaxaura sp. to brown and green foliose macroalgae like peacock’s tail (Padina sp.), forkweed (Dictyota sp.) and turtleweed (Chlorodesmis sp.).
Some foliose macroalgae, like forkweed, can colonise the sand flats adjacent to the rocky reef, particularly where the sand has been stabilised by seagrass.
Marine life
While the coverage of articulate coralline and foliose macroalgae is typically low compared to turf algae, they still provide shelter and food for numerous fish and invertebrates.
Green turtles and numerous species of surgeonfish feed on the various types of algae found throughout the aquatic reserve. Many more species, including eastern blue groper, forage for prey that live among the various types of algae.
Marine snails, crabs and sea hares feed on macroalgae. Some sea hare species will adopt the colour of the macroalgae they consume, displaying red, green or brown pigmentation and creating an effective camouflage.
Male crimsonband wrasse resting among green algae
(Photo: Rudi Vir)
Articulate coralline algae and foliose macroalgae is found in deeper or more sheltered areas of the aquatic reserve (Photo: Ecological Service Professionals)
Luzon sea star moving among forkweed and peacock’s tail algae (Photo: Ecological Service Professionals)
Male crimsonband wrasse swimming above fork weed (Photo: Gary Shuttleworth)
Spotted wobbegong nestled in a bed of red articulate coralline algae (Photo: Gary Shuttleworth)
Cuttlefish (Sepia sp.) in green, brown and red macroalgae habitat (with turf algae adjacent) (Photo: Rudi Vir)
Lizard fish amongst red and green algae (Photo: Hamish Malcolm)
