Robot fish that look a lot like sharks are the latest research tool for University of Hawaii oceanographers.

In concert with scientists at the Monterey Bay Aquarium Research Institute in California, UH marine scientists plan to deploy a small fleet of long-range, autonomous underwater vehicles that can collect and record seawater samples without humans at the helm.

These new robots, with a range of more than 600 miles, will allow researchers to track and study the tiniest ocean life in unprecedented detail. That in turn is important to our understanding of global climate change.

Ocean microbes produce at least 50 percent of the oxygen in our atmosphere while removing large amounts of carbon dioxide, according to a March 15 release. These bugs also form the foundation of marine food webs, including those that support global ocean fisheries.

The robot fish will “use their own ‘eyes and ears’ to detect important oceanographic events like phytoplankton blooms,” said UH oceanography professor Edward DeLong. “These new underwater drones will greatly extend our reach to study remote areas, and also will allow us to sample and study oceanographic events and features we can see by remote satellite imaging, even when ships are not available.”

In late February engineers from Monterey Bay finished the construction and testing of three new autonomous underwater vehicles, or AUVs, and delivered them for their first deployment in Hawaii waters. The research vessel Falkor, operated by the Schmidt Ocean Institute of Palo Alto, Calif., left March 10 for sea trials.

In blog entries last week on the institute’s website, UH communications project manager Elisha Wood-Charlson said the vessel and UAVs named Opah and Aku had found, characterized and tracked an ocean eddy north of Maui. Eddies are water systems that move in opposition to the main current of the greater ecosystem, creating a swirling system like a whirlpool.

The next task is to sample the eddy’s chlorophyll at a depth of about 300 feet, Wood-Charlson said.

As the “bots” move through the ocean, they collect information about temperature, chemistry and chlorophyll — an indicator of microscopic algae — and send the data to scientists on shore or on a nearby ship. They also have an integrated environmental sample processor (ESP), a small automated laboratory that collects and preserves seawater samples, allowing researchers to discern the bugs’ genetic material and proteins.

The Monterey Bay institute has been developing such labs for about 15 years. The latest, the third generation, are 8 to 10 inches in diameter — one-tenth the original size — and were designed specifically to fit into a long-range AUV.

“When we first talked about putting an ESP in an AUV, I thought to myself, ‘This is never going to happen,’” said Jim Birch, a lead engineer at the institute, in a statement. “But now I really think this is going to transform oceanography by giving us a persistent presence in the ocean — a presence that doesn’t require a boat, can operate in any weather condition, and can stay within the same water mass as it drifts around the open ocean.”

On the current cruise, when the robots return to the surface and are recovered, UH-Manoa researchers extract DNA from the filters. This information will provide insight into the eddy’s duration, stability and influence on the ocean systems, and will improve ocean models that are critical to predicting trends.

“Although this fleet of AUVs will never replace our need for a capable research vessel, it will provide much needed access to the sea and the collection of novel data sets that would not otherwise be possible,” said UH oceanography professor David Karl, co-director, with DeLong, of the Center for Microbial Oceanography: Research and Education.