As SeaWorld prepares to celebrate its 60th anniversary this weekend at its San Antonio park, a group of animal rights activists is ready to provide counter-programming highlighting what it calls “60 years of misery” the amusement company created for aquatic mammals. A pod of PETA supporters plans to protest outside the gates of SeaWorld San Antonio starting at 10 a.m. Saturday, accusing the park of abuse against dolphins and orcas.