Martek Biosciences Corporation has posted a fall in half-year profits thanks to rising operating expenses.

The US firm, the company behind life'sDHA, recorded net income of US$7.6m for the six months to 30 April, down from $125.7m a year earlier.

The drop in profits came despite a rise in turnover. Sales reached $146.9m, up from $133.1m a year earlier.

CEO Steve Dubin expects sales and margins to rise in the second half of the year. "While Martek's year-to-date earnings per share are currently below prior year levels, I expect Martek's higher revenues and gross margin improvement in the second half of the year to generate full year earnings that exceed 2006 results," Dubin said.