Posted on: Friday, June 1, 2001

Algae bloom spreads along Maui coast

By Timothy Hurley
Advertiser Maui County Bureau

WAILUKU, Maui — An algae species that plagued the waters off West Maui 10 years ago and sparked more than $1 million in government-backed research apparently is mounting a comeback.

State aquatic officials report that a bloom of the wispy green Clado phora sericea began last month and has been detected along the coast of West Maui and in areas off South Maui.

The seaweed that some describe as glowing in the water is floating and tangling on reefs and coral heads, said Skippy Hau, aquatic biologist with the state Department of Land and Natural Resources.

The bloom apparently started in West Maui around May 7, Hau said. Specimens were collected a few days later, and it was seen on shores from Kapalua to Ka'anapali.

At Honokowai, Cladophora sericea was found throughout the water column (from the ocean floor to the surface), and on the sea bottom more than 100 yards offshore. It also was present in the waters off Olowalu.

Reports indicate the seaweed has penetrated a 110-foot underwater pinnacle off South Maui that is a popular diving spot, and is present at a Lana'i snorkeling spot known as First Cathedral. It also has been reported at Ulua Beach in Wailea and was seen from a plane by a fisherman's spotter.

Hau said he is hoping trade winds pick up and change ocean currents, helping to direct some of the algae offshore.

In the summers of 1989 and 1991, Cladophora sericea filled whole columns of West Maui ocean, tangling on reefs and killing coral heads. Those episodes fueled fears about the degradation of Maui's nearshore waters, prompting Congress to allocate more than $1 million for algal bloom research.

A dozen major investigations were unable to pinpoint the cause of the West Maui algae episodes. But they did indicate the blooms were driven not only by nutrients from fertilizers and surface runoff, but by changes in climate, currents and precipitation.

Cladophora sericea is thought to be a native species, or one that was introduced long ago. It normally exists in relatively low concentrations.

The best previous hypothesis was that the blooms were linked to rainfall and runoff, since the winters before 1989 and 1991 experienced heavy rainfall, said Wendy Wiltse, a Honolulu-based U.S. Environmental Protection Agency scientist who oversaw the research as coordinator of the West Maui Watershed Management Project.

"But that doesn't fit with what's being seen this year, so apparently it's not related to rainfall and runoff," she said.

This algal bloom does not appear to have reached the levels of a decade ago — at least not yet.

Chad Wylie, operations manager of Atlantis Submarines in Lahaina, said crews noticed the seaweed in greater abundance in waters off Puamana for a two-day period two weeks ago, but it hasn't been as bad since.

"It was nothing like it was 10 years ago," Wylie said. But, he added, the mere fact his crew noted its presence is enough to cause some worry.

Greg Howeth of Lahaina Divers said none of his customers or crews have complained to him about masses of seaweed.