MILFORD — U.S. Sen. Chris Murphy took a peek into the private and curious world of clams, scallops and oysters Tuesday in a visit to the National Oceanic and Atmospheric Administration’s Milford Lab, which is carrying out critical research on how best to manage Connecticut’s $30 million aquaculture and shellfish industry.

Scientists explained that a healthy shellfish industry means a lot more than enjoying a plate of oysters at a raw bar. According to research ecologist Julie M. Rose, filter-feeding clams and their mollusk brethren play a vital role in keeping Long Island Sound clean.

“If you look at the dollar value that shellfish provide — just in terms of water quality — the Connecticut shellfishing industry provides about $6 million per year in ecosystem services,” Rose said. “And if the shellfish industry expanded to fully occupy all of the leased beds, this number could grow to about $14 million annually.”

Without clams, oysters and scallops, she said, waste treatment plants along the shore and even in upstate towns and cities would have to invest in far more effective equipment costing millions of dollars to get the same water-cleansing effects that mollusks provide.

Rose’s research deals with how best to grow and feed shellfish their favorite foods — phytoplankton and zooplankton. The plankton is cultivated on an upper floor, and it’s fed to the clams and oysters in the basement.

“We deliver it to them in hand carts,” she said. “Big, huge bottles of plankton in hand carts.”

After the tour, Murphy, D-Conn., said getting Washington to fund research has been an uphill slog in recent years.

“There’s a war on science in Washington today, so it can be difficult sometimes to invest on science like this,” he said. “This is farming, too, just like what goes on in Iowa, Kansas and Ohio. It is difficult sometimes to convince senators that this is food production, too, much the same as what goes on in the Midwest.”

Murphy’s visit to the NOAA lab was followed by stops in Norwich, Darien and Greenwich, where he spoke to others concerned with the Long Island Sound biosphere, which in some ways is doing well, but in others, not so well. He spoke to Darien Seafood Market owner Roger Frate to learn what the near-collapse of Long Island Sound’s lobster population has meant to his business.

The Milford NOAA lab, on Rogers Avenue, was established in the 1920s. It is funded by federal grants from the National Marine Fisheries Service. The lab developed “The Milford Method” of encouraging clam and oyster reproduction, techniques that are used in commercial shellfish beds worldwide today. The lab continues to refine and advance shellfish hatchery research.

Murphy said the Milford NOAA lab receives about $2 million a year in federal funding.

Many species of shellfish, as Murphy learned, are hermaphroditic. Oysters, for example, start off as one sex and change gender as they get older, a condition known as sequential hypothyroidism. Scallops are simultaneous hermaphrodites — they produce both sperm and eggs every day.

“They’re male for 15 minutes and then they’ll be female for the next 15,” said NOAA researcher Sheila Stiles. “We have to keep switching them out of the pools here in the lab so they won’t fertilize themselves — we don’t want them to inbreed.”

She added that scallops have “little blue eyes” lined up along the inner edge of the shell.

“They can see me coming,” she joked. “They don’t want to bite the hand that feeds them.”