U.S. Sen. Chris Murphy on Thursday toured an oyster farm in Norwalk to learn more about the shellfish industry.

The visit came days after the senator released his Long Island Sound investment plan, in which he called for ways to clean and preserve the body of water.

According to Murphy, keeping the Sound clean is important to protect businesses such as Copps Island Oysters in Norwalk. He says a report released by environmental program Harbor Watch gave Norwalk Harbor a "C+" rating due to pollutants in the water.

The senator is now asking for a 10 to 15 percent increase in federal funds to protect the Sound. Part of his plan would include reducing nitrogen levels and ocean acidity to improve water quality.

Murphy adds that there are nearly 79,000 jobs that depend on the Long Island Sound -- jobs that may be threatened if the shellfish and other species there decrease.