One of the country's biggest and longest-running artificial reef research projects is about to widen its scope, and the payoff could be healthier grouper in the Gulf of Mexico, a University of Florida researcher says.

Over the last 17 years, UF researchers have built and placed a 26-mile line of artificial reefs in the Gulf and studied its impact on gag grouper, a popular game and food fish.

The reefs give shelter that researchers believe helps young gag grouper grow to adulthood and replenish heavily harvested populations.

There are many reasons for the massive project. Because artificial reef building is often publicly funded, there is interest in knowing how to best use artificial reefs. And knowing how fish use the reefs is key to helping manage fish populations.

Jon Dodrill, a Florida Fish and Wildlife Conservation Commission environmental administrator, calls the project significant.

"Just in the sheer number of years involved in the planning process and looking ahead at continued monitoring, continued construction…it's one of the largest artificial reef projects that's been undertaken," he said.

The first phase of the reef project began in 1990.

In that phase, called the Suwannee Regional Reef System, Lindberg's team placed 1,350 one-ton concrete cubes on the ocean floor, stretched over a 26-mile strip about 20 miles off the northwest Gulf coast.

The reefs — assembled in four- to 16-cube formations — were then studied, the fish counted, their condition monitored and their every habit scrutinized.

The gag grouper reproductive cycle begins when harem of a few males and many females spawn 100 miles offshore. When the eggs hatch, the current carries the tiny fish to seagrass beds close to shore, where they spend their first summer. Over the next few years they leave their seagrass nursery and head for deeper water, where the survivors themselves spawn.

Lindberg and his team think they may help the gag grouper population with the new artificial reef system, called the Steinhatchee Fisheries Management Area. That system will include 1,600 cubes placed inside a 100-square-mile triangle.

The new reefs — just north of the first system — will shelter the fish from predators as they make what otherwise would be a precarious journey across the mostly flat ocean floor. Lindberg hypothesizes the trek to spawn causes a "bottleneck" in the gag grouper's ability to reproduce.

Despite the reef project's cost and time, Dodrill said his agency had no qualms.

"This is a pretty carefully thought-out design," Dodrill said. "Something like this takes expertise and time and money — three tough things to bring together in one place."