US Representative Edward J. Markey is leading the race for the Democratic Senate nomination while former US attorney Michael J. Sullivan is ahead in the battle for the GOP nomination, according to a new WBUR poll released this morning.
But many voters said they are undecided or have never heard of the candidates, indicating the race remains fluid a little more than a month before voters head to the polls for the April 30 primary.
Markey, a Malden Democrat heavily backed by the national Democratic establishment, leads his rival, US Representative Stephen F. Lynch of South Boston, by 11 percentage points among likely Democratic voters, 35 percent to 24 percent, according to the poll.
But about 30 percent of those surveyed said they have never heard of or are undecided about both Lynch and Markey.
Respondents also said they had a more favorable view of Lynch than Markey. Either one would hold a lead of at least 17 percentage points over any of the GOP candidates in a hypothetical general-election matchup.
On the Republican side, Sullivan leads with support from 28 percent of likely GOP voters, compared to 10 percent for state Representative Daniel B. Winslow and 8 percent for Gabriel E. Gomez, a private equity investor and onetime Navy SEAL.
Even more voters -- between 30 and 36 percent, depending on the candidate -- said they had never heard of or were undecided about the GOP candidates.
The live telephone survey of 610 likely voters was conducted between March 19 and 21 by the MassINC Polling Group and has a margin of error of plus or minus 4.1 percentage points.
The results comes as the Republican and Democratic candidates prepare for 30-minute debates Wednesday on NECN. The Republican candidates will debate again on Thursday in Springfield.
Michael Levenson can be reached at MLevenson@globe.com.