It’s been 40 years since William W. Warner’s Pulitzer Prize-winning book introduced us to the creature that’s been captivating diners and scientists alike ever since.

In Beautiful Swimmers Revisited, a documentary whose title was taken from Warner’s book, Bay Journal columnist Tom Horton and photographer Dave Harp catch up with the iconic blue crabs that are the subject of the original work.

The film, which premieres this month, is an initiative of the Bay Journal and was directed and co-produced by Sandy Cannon-Brown’s VideoTakes, Inc., with support from The Shared Earth Foundation and other donations.

Horton narrates the film’s journey around the Bay to look in on those who catch, study and eat blue crabs. He meets with scientists from the Smithsonian Environmental Research Center and the Virginia Institute of Marine Science, whose expertise on blue crabs is unmatched, as well as crabbers who’ve been pulling them from the Bay for generations.

The focus of the film’s narrative isn’t a person or even the crab so much as the scientific process that has helped us better understand them: the annual winter dredge survey that Maryland and Virginia have now conducted for decades.

“It sounds kind of simple — ‘Let’s go count crabs,’” Horton said. “But if you don’t learn how to count crabs, you have a hard time trying to figure out how to manage them.”

The film shows some of the faces behind the surveys that have done just that for about 20 years, with crabbers, watermen and scientists braving the elements each winter to collect the crucial data. That information has created a long-term framework for understanding the species, allowing fisheries to be better managed over the years.

Harp’s iconic images of the Bay, fishermen and the beautiful Callinectes sapidus weave the story together as it’s told from kayaks, fishing boats, research vessels and Horton’s 21-foot skiff. The crew traveled from Baltimore Harbor to Virginia’s Tidewater to retrace the life cycle and story of the crab.

The film demonstrates how science has evolved since Warner’s day to better understand the behavior of this enigmatic shelled creature and how it fits into the complex ecology of the Chesapeake Bay. Scientists now know, for instance, that the way the wind blows across the mouth of the Bay can have a huge impact on the number of blue crabs that show up in survey nets and crab pots each year, Horton said.

“That was not understood when he (Warner) wrote Beautiful Swimmers, he said.

Now, Horton said, if there are unknowns about blue crabs, “it’s what kind of system will be best for crabbers and for crabs. And that’s an area that’s as political as it is scientific.”

Beautiful Swimmers will premiere at 4:30 p.m. March 19 at the Environmental Film Festival in the Nation’s Capital at American University. For details about the festival, visit dceff.org.

Another screening will take place at 7 p.m. April 13 at Salisbury University in Salisbury, MD.

Watch the Bay Journal for information about future screenings.