Sen. Benjamin Cardin is launching a television campaign to bolster his reelection bid, hitting the airwaves with what his staff calls “a substantial six-figure buy.”

Cardin’s ads come as Maryland’s April 3 primary approaches, with state Sen. C. Anthony Muse (Prince George’s) challenging the incumbent for the Democratic nod. Cardin spokeswoman Sue Walitsky said the ads were timed not for the primary but to take advantage of a quiet period in the state, when airtime is cheaper.

“Senator Cardin’s communication with voters will continue from now until November, but this is an opportunity in the lead-up to the primary to reach people when they are starting to pay attention to this year’s election without the clutter that will come in the fall,” Walitsky said.

The first spot, “My Friend Ben,” goes on the air this week, featuring a young girl narrating the story of how Cardin wrote a law to help ensure children get proper dental care.

The second ad, which will begin airing next week, highlights Cardin’s efforts to preserve oyster beds in the Chesapeake Bay and boost the oyster industry in the process. The spots will appear on cable television in the Washington media market, and both cable and broadcast channels in Baltimore.

On the Republican side, former Secret Service agent Daniel Bongino is battling with former Bush administration official Richard Douglas and a handful of others for their party nomination. In a fundraising e-mail sent Monday, Bongino’s campaign said “Cardin is about to spend $1 million on media advertisements,” suggesting it was evidence that “he is weak going into the general election!”

As of Dec. 31 Bongino had raised $130,000 and had $15,000 left in the bank, while Cardin had $2.7 million on hand after raising a total of $4.5 million for the cycle.