U.S. Sen. Robert Menendez is in the lead for a seat in the Senate over former pharmaceutical executive Bob Hugin, but by a slim margin, according to a Quinnipiac University Poll released Wednesday.

Menendez has a 43 percent to 37 percent lead over Hugin among Democrats. This compares to a 49 percent to 32 percent lead Menendez had over Hugin in a March poll by Quinnipiac.

The most recent poll found there’s a wide racial gap in the numbers, as Hugin leads 47 percent to 38 percent among white voters and Menendez leads 51 percent to 18 percent among non-white voters.

Among important voter issues, ethics is the top deciding factor when voting for U.S. Senator, 25 percent of New Jersey voters said. One-fifth listed taxes, 19 percent said health care, 14 percent said immigration and 14 percent said the economy.

“As Sen. Robert Menendez sees his once dominant lead whittled down to single digits, New Jersey voters are sending a clear message. They are troubled by the ethics cloud hanging over him,” said Mary Snow, polling analyst for the Quinnipiac Poll.

Among approval ratings, voters give Menendez a negative 40 – 47 percent approval rating and a negative 29 – 47 percent favorability rating. Hugin gets a slightly positive 24 – 20 percent favorability rate, but 54 percent of voters said they haven’t heard enough about him to have an opinion.

“While voters prefer Sen. Menendez over Republican Bob Hugin in deep blue New Jersey, they give the incumbent negative approval and favorability ratings,” Snow said.