Demand to ship petrochemicals and other bulk products on U.S. waterways started to return in March, according to the head of the country's largest barge operator.

Joe Pyne, chief executive of Kirby Corp. (KEX), said Wednesday that market conditions had improved after rampant destocking from November through February.

"The inventory had [reached] levels unacceptable to our customer base," said Pyne at a transportation conference hosted by JPMorgan. "They are trying to figure out where the demand is."

Pyne said the softness in the market afforded Houston-based Kirby with M&A opportunities having already completed 40 deals in the fragmented U.S. barge market.

The company operates almost 1,000 barges along the Mississippi River and other large inland waterways, as well as along the Gulf coast where the U.S. petrochemical industry is focused.

Two-thirds of its business is from transporting petrochemicals for customers including Exxon Mobil Corp. (XOM) and Dow Chemical Co. (DOW), whose chief executive this week signaled an uptick in demand for some chemical products.

Kirby shares were up 3.8% at $22.55 in midmorning trade.

-By Doug Cameron, Dow Jones Newswires; 312-750-4135; doug.cameron@dowjones.com