Retailers are bracing for lackluster sales on Black Friday, the first shopping day after Thanksgiving and the traditional start of the holiday shopping season.

Sixty-eight percent of marketers at 100 of the nation's largest retailers said they expect this year's Black Friday sales to be flat, according to a survey by BDO Seidman, a Chicago-based professional services firm. Just 16 percent are anticipating increases.

On average, Black Friday sales are expected to increase by just 1.2 percent, compared to 8.3 percent last year, the firm reported.

"This is down significantly from last year," Ted Vaughan, a partner in BDO Seidman's retail and consumer product practice, said in a statement.

By contrast, online sales are expected to fare much better, with roughly half of respondents saying Web-based purchases would increase significantly over last year. Gift card and electronics sales are also expected to be stronger, the survey found.

"Gift cards will be popular this year because they allow the end user to decide on the gift based on their personal needs," Vaughan said.