Jonathan Walker, who has served as president and CEO of the Metropolitan Tucson Convention and Visitors Bureau for 18 years, has announced his retirement, effective March 2012. According to a spokesperson for the bureau, Walker's decision was based on personal reasons. "Walker's continued presence at the MTCVB over the next six months will help ensure a seamless leadership transition," said MTCVB chair Lynn Ericksen in a statement about Walker's retirement.