More than 100 scientists joined a two-week marine life survey of Kaneohe Bay and discovered hundreds of new species and what appears to be the beginnings of an aggressive algae invasion.

The results of the Smithsonian Institution-organized collection and biological assessment conducted from May 20 to June 2 were released earlier this month.

The survey collected more than 3,700 representative specimens of fish, invertebrates and algae that are also being documented through high-resolution photography and genetic characterization, or barcoding.

A year in the making, the marine species inventory will form the basis of a lasting database of all the living things of Kaneohe Bay, from bacteria to fish.

“When it all came together, it was astonishing how well it worked,” Mary Hagedorn, director of MarineGEO Hawaii, said of the survey operation.

More than 100 professionals from 24 institutions in nine countries joined in the research, with 28 students from high school to postdoctoral fellows training alongside six teams of expert scientists.

The project is part of the Smithsonian’s Marine Global Earth Observatory research program, also known as MarineGEO, described as “the first long-term, worldwide research program to focus on understanding coastal marine life and its role in maintaining resilient ecosystems around the world.”

The program teamed up with the University of Hawaii at Manoa’s Hawaii Institute of Marine Biology to create MarineGEO Hawaii, the network’s first partner site based out of the institute’s Coconut Island laboratory.

Establishing the first collections for the Smithsonian MarineGEO program worldwide, the effort not only collected thousands of species, but discovered hundreds of new invertebrates and meiofaunal species, or tiny animals that live in marine sediments.

Hagedorn said the impressive haul of discoveries could generate more than 50 scientific articles.

Among the new invertebrates were an astonishing 150 sponge species previously unseen in Hawaii. Among those, roughly a third of them are new species, Hagedorn said. Keep in mind, she said, only about 10 sponge species were previously known to exist in Hawaii’s largest sheltered body of water.

Not everything discovered by the collection teams was met with happy faces. Hagedorn said the algae team found acres of Avrainvillea amadelpha, an aggressive algae known as leather mudweed, in the northern section of the bay near Mokolii islet, also known as Chinaman’s Hat.

The alien species apparently migrated to the bay from Maunalua Bay and other leeward locales, where it has overwhelmed native seagrass beds.

“If it goes everywhere into the bay, it would be a very bad thing,” Hagedorn said.

Bruce Anderson, administrator of the state Division of Aquatic Resources, said he is aware of the infestation, and a multiagency team is working on it.

“It’s a difficult one to get a handle on. Our management options are limited,” Anderson said.

“This stuff seems to be spreading along both the Windward coast and Leeward coasts of Oahu. It is found at Barbers Point, Maunalua Bay, Bellows and now the northern side of Kaneohe Bay. And it is not just in shallow water. It is found at depths of 100 feet or more. It will be very difficult to control or manage,” he said.

As for the MarineGEO study, Anderson said he welcomes an effort that will help Kaneohe Bay resource managers well into the future.

The DNA barcoding will be especially helpful, officials said. Aquatic organisms shed cells into their environment. Once a DNA barcode is known, a simple water sample and DNA analysis can detect the presence of a species.

According to a report about the survey, “This information is especially important in light of the two near-extinction events that occurred in Kaneohe Bay: the first during the dredging in the 1930s and the second in response to the sewage outfalls in the 1970s when 95 percent of the coral in the bay died. Species diversity information is critical for effective management plans.”

This isn’t the first time specimens have been pulled from Kaneohe Bay for scientific collections. Such collections have been made in the bay since the early 1900s, with these surveys compiled over time into species lists. But no comprehensive survey has ever been made of Kaneohe Bay at one time, officials said.

Hagedorn said her survey collected about half of the known fishes of Kaneohe Bay, missing some of the more cryptic species. She said she’s hoping that next year her team will get another crack at collecting the fish that weren’t seen this time.

The collections will be cataloged and maintained at the Smithsonian, the University of Florida and the Bishop Museum, three institutions capable of maintaining these collections.

In addition to its long-term monitoring studies and field experiments, MarineGEO Hawaii is expected to study the crossroads of science and culture in the islands, drawing on traditional knowledge regarding conservation management. The studies are also expected to offer educational opportunities and training to students and scientists from around the world.