Houston-based Hercules Offshore says it will lay off 324 offshore Gulf of Mexico workers, about 15 percent of its workforce, because of a decline in business.

The drilling rig contractor sent a letter to the Texas Workforce Commission last week, saying the company would lay off the employees by the end of the year.

The layoffs involve employees who work out of Port Fourchon, Grand Isle, Berwick, Cameron, Abbeville, Lafitte, Larose and Venice.

The company announced an $88.6 million third-quarter loss on Oct. 23.

John T. Rynd, Hercules CEO and president, said the company’s business outlook may not improve until sometime next year.