Horizon Lines Inc., the shipping line that is the No. 2 carrier of ocean cargo between the Mainland and Hawai'i, said net income fell during its second quarter compared to a year ago, as volume slipped and its Puerto Rico trade declined.

The Charlotte, N.C.-based company said its Hawai'i volume has been impacted by lower tourism and some other factors, but that some of the dropoff has been offset by shipping of materials for commercial and military construction.

Hawai'i "unemployment, although it has increased from 2.6 percent, is a relatively low number of 3.8 percent in the state," said John Kennan, president of the company's Horizon Lines LLC unit, on a conference call with investors.

"And commercial and military construction is offsetting some of the soft residential sector that we're experiencing in the state."

Horizon reported profit fell to $7.24 million, or 24 cents a share.

That was a 24 percent decline from the $9.56 million, or 28 cents a share, earned a year earlier.

Operating revenue increased to $330.9 million from $295.7 million a year earlier.

The earnings beat Wall Street's estimates. The average estimate of the average forecast of five analysts surveyed by Bloomberg L.P. were for a profit of 22.5 cents a share. Horizon's stock price rose $2.22 to $11.14.

"We were able to effectively mitigate the impact of steep fuel cost increases in the quarter through a combination of conservation, strict vessel scheduling and fuel cost recover measures," said Chuck Raymond, chairman, president and chief executive officer.

Horizon had little to say about a U.S. Department of Justice investigation into possible anti-trust violations when it came to shipping prices in its domestic ocean shipping businesses.

The probe came to light on April 17 when Horizon disclosed federal agents had served search warrants in an investigation of pricing practices among carriers serving Puerto Rico.

Matson Navigation Co. later said it received a grand jury subpoena for documents related to pricing in domestic markets.

In a regulatory filing yesterday Horizon said 35 class-action lawsuits had been filed connected to the pricing investigation. It said it wanted to consolidate the Puerto Rico-related cases in Florida and the Hawai'i-related cases in Washington state.