Fond du Lac’s largest employer is laying off hundreds of workers. Mercury Marine has announced it will cut nearly 300 jobs at its Fond du Lac headquarters. The company says the layoffs are due to a “softening of consumer demand” in certain markets. The company employs more than 3,500 full-time workers in Fond du Lac. Merc says the company has a $5 billion annual economic impact in Fond du Lac County.