According to William Magruder, a marine botanist with Bishop Museum who also heads the state’s Algae Task Force, several species of algae have become nuisances in Maui waters.
Most notorious have been species of the Cladophora genus. In 1989, Cladophora vagabunda was thought to be in bloom along the West Maui coast. Magruder is not certain whether that identification was correct, since subsequent blooms have been identified as Cladophora sericea. (The illustration on page 1 is a drawing of Cladophora fascicularisi, which has been taken from William Randolph Taylor, Marine Algae of the Eastern Tropical and Subtropical Coasts of the Americas [Ann Arbor, 1960], page 669.)
The Cladophora algae have been described as “filamentous and hairlike, growing in tufts, mats, or in loose floating masses which resemble wet, green hair… The individual filaments are sparingly to repeatedly branched so colonies are usually quite entangled.” (See Charles James Hillson, Seaweeds [Pennsylvania State University Press, 1976], page 16.)
Farther north along the coast, and along Maui’s North Shore, Hypnea musciformus has been in frequent bloom. This is a species of edible red algae believed to have been introduced to Hawai’i the 1970s, when it was released into Kane’ohe Bay. Since then, it has been spotted in waters around all the islands except for the Big Island. (Magruder says he fears the day when it hits Hilo Bay – a day that, he says, will surely come.)
A third species of algae seems to have taken up permanent residence in Kahului Bay: Ulva fasciata, also known as green sea lettuce. It is found all over, but is especially rampant in Kahului Bay.
Algae on the whole have gotten a bum rap by the few species that make nuisances of themselves, Magruder maintains. People are in the main ignorant of the important role algae plays in reef formation and coral growth, to say nothing of the vital link it represents in the marine food chain.
Magruder notes that there is no guide to the algae of the Pacific Islands. It is a void that he is attempting to fill.
Volume 3, Number 4 October 1992