NEW YORK (Reuters) - SeaWorld Entertainment Inc SEAS.N shareholders voted against the re-election of its chairman on Wednesday, according to people familiar with the matter, after investors revolted against a bonus incentive payout.

Visitors attend the animal theme park SeaWorld in San Diego, California March 19, 2014 REUTERS/Mike Blake

The shareholder vote shows how investors, even in an uncontested board election, are increasingly voicing their frustration with board members on matters related to executive and director pay.

Chairman David D’Alessandro received more “withhold” votes than “for” votes at the annual meeting on Wednesday, a proxy voting result that means shareholders effectively voted him off the board, according to people familiar with the matter, who did not want to be named because the vote tally is not yet final.

The result means that D’Alessandro is required to offer his resignation, according to company bylaws. The board must then disclose within 90 days what its intentions are in relation to the offer.

“The board will continue to proceed in the best interest of shareholders following this year’s annual meeting,” Orlando, Florida-based SeaWorld said in a statement to Reuters.

SeaWorld announced in March that China’s Zhonghong Zhuoye Group Co Ltd agreed to buy Blackstone Group’s 21 percent stake in the theme park operator for $23 per share, or $429 million.

The following month, SeaWorld disclosed in a securities filing that in connection with the sale, it would be paying out special bonuses to certain employees that dated to SeaWorld’s 2013 IPO.

The original agreement granted D’Alessandro, ex-CEO Jim Atchison and about 60 key employees a chunk of restricted shares to be paid out if SeaWorld achieved certain goals, including an investment return multiple of 2.75 times Blackstone’s invested capital.

Based on the price Zhonghong paid, the achieved multiple fell just shy of that threshold, the company said.

What sparked the ire of investors was that despite missing the target, SeaWorld still agreed to make the restricted share payouts, with D’Alessandro and eight of the company’s senior executives forfeited 40 percent of the sum.

Proxy adviser Glass Lewis recommended shareholders vote against D’Alessandro and another director at the annual meeting, citing the stock payouts. Proxy adviser ISS recommended shareholders vote against SeaWorld’s compensation plans at the meeting, calling the restricted share payout “concerning” given the company’s poor financial performance. SeaWorld’s shares have fallen by half since its IPO. Shares of the $1.5 billion company rose 6.7 percent on Wednesday to $17.07 per share.

“We have spoken to investors who share those concerns so a negative vote and some degree of board shakeup seem possible to us,” FBR analyst Barton Crockett said in a June 9 note.

The company said in a letter to shareholders prior to the annual meeting that after considering certain factors, including achieving 97 percent of the investment multiple threshold, that it was appropriate for morale and employee retention to make the payouts. None of the company’s new leadership team were eligible for the restricted shares, SeaWorld said.

“Most of the covered individuals had been working for several years to stabilize the company,” SeaWorld said in its letter to shareholders.

SeaWorld, which operates 12 theme parks in San Diego, Orlando and San Antonio, faced criticism after the release of the 2013 documentary “Blackfish,” which depicted the captivity and public exhibition of killer whales as inherently cruel.

The company said last year it would stop breeding killer whales in captivity.