San Diego (tca/dpa) — When SeaWorld San Diego marked its half-century anniversary 10 years ago, it was enmeshed in a public relations quagmire following the release just a year earlier of “Blackfish,” the searing anti-captivity documentary that threatened to upend the theme park’s identity as the home of Shamu the beloved killer whale. What a difference a decade makes. As the park embarks on a yearlong celebration of its 60 years in business, much has changed, even in the past 10 years. While the San Diego park has yet to exceed — or even reach — its peak annual attendance milestone of 11 year…