NIHOA, Northwestern Hawaiian Islands — A heavy rolling swell west of Nihoa prevented one research boat from launching and required three tries to recover another Saturday, hampering research efforts.

NOAA dive boat skipper Jason Kehn said it was the roughest open-sea recovery he had experienced and the excitement at sea put a halt to further scheduled scientific investigations at Nihoa.

The NOAA research ship Hi'ialakai moved on to French Frigate Shoals, after the Hi'ialakai's captain, Scott Kuester, and mission chief scientist Randy Kosaki determined that there was little chance researchers could get to Nihoa's shoreline waters as scheduled yesterday.

A team of 20 scientists are on the ship for a 25-day, wide-ranging survey of the waters of Nihoa, French Frigate Shoals and Gardner Pinnacles in the Northwestern Hawaiian Islands, and Johnston Atoll, which lies 500 miles south of French Frigate Shoals.

The marine biologists have many skills. In addition to knowing their undersea creatures, most are skilled with computers, certified divers, designers of specialized tools for conducting their work, accomplished at complex genetic analysis and daredevils as well.

As when shark-tagging biologist Carl Meyers snagged a swaying heavy metal shackle the size of a loaf of bread, while riding the bow of a small boat leaping like a bronco alongside the looming steel hull of the Hi'ialakai. Kehn was doing the same thing at the back of the boat, but then it's his job. In this complex, dangerous-looking dance, biologist Jill Zamzow also grabbed a rope with a flailing shackle out of the air and snapped it onto a ring on the dive boat.

Hi'ialakai's boats have large steel hooks forward and aft, and the boats are hoisted onboard after twin cables from two-armed crane are shackled to the boat, which is hoisted up the side of the ship — in our case — with seven people and dive gear still inside.

Divers in our boat had been doing fish work. They collected samples of reef fishes for genetic studies to compare them to those in the main Hawaiian Islands. They set a listening buoy in 60 feet of water, which will record the presence of fish that have been implanted with acoustic transmitters.

And they trolled the circumference of Nihoa in the stormy seas in hopes of catching the bottom fish known as uku, without success. Had they been caught, the uku would have had transmitters surgically inserted into their belly cavities. The buoy will still pick up the signals from already-tagged fish.

One other dive boat had been successfully launched at Nihoa, and its divers were working on corals and crustaceans.

They clipped small pieces off corals for eventual studies of coral disease and of relationships between these corals and those in the main Hawaiian Islands. They also caught small crabs and shrimp, often taking just a leg that would grow back. A tiny leg provides enough material to conduct genetic studies on the crustacean.

GENETIC KEYS

Stephen Karl, a population geneticist with the University of Hawai'i's Hawai'i Institute for Marine Biology, said there are many questions genetic work can address.

"When I swim over coral, I see one individual that's diseased, and right next to it, another one that's healthy. I want to know why," Karl said.

It might be chance that the disease hit one and not the other, and it might be some tiny environmental difference. But it might be something genetically different about them that made one susceptible and one not, he said.

"I want to look at each individual and see if coral diseases are related to genetics," Karl said.

For the reefs themselves, and for people who live around reefs, the research has significant implications. For example, if a reef's corals are all clones of each other — having the same genetic makeup — then they are likely to be vulnerable to disease as a group.

But if the corals are genetically diverse, there's a good chance some will have a resistance to the disease and survive. Knowing that ahead of time can help natural resource managers determine whether they need to act aggressively when they see a particular problem along the coastline.

Biologist Iliana Baums is looking at coral genetics in another way, trying to determine how closely different coral populations on different islands in Hawai'i are related to each other. Are coral larvae from one island seeding other islands, or do they mainly stay close to where they were spawned?

"What happens if one population is destroyed? How do they get reseeded?" Baums said.

MYSTERIOUS BACTERIA

Another scientist, Jennifer Salerno, is looking into the bacteria that grow on corals. Researchers know they're present on corals, but what are they doing there?

"We really don't know what role they are playing," she said. Some possibilities: Some may cause disease, some may provide corals with antibiotic qualities to prevent disease. Some could be in a kind of symbiotic relationship with corals, and could be providing them with food.

As with the other work under way, these are topics nobody knows a lot about.

"This is an emerging field: marine microbiology and coral reef ecology," Salerno said.

Reach Jan TenBruggencate at jant@honoluluadvertiser.com.