Capetonians don’t know who to blame for the disappearance of their great white sharks: The orcas that eat them, the fishermen who sell their prey to Australia for use in fish-and-chips shops or gradual ecological change. The world’s biggest predatory fish haven’t been seen this year in False Bay, which lies off the city’s eastern coast, according to scientists and cage-diving operators. While the absence may be temporary it’s creating concern because, along with vineyards, the iconic Table Mountain and world-class restaurants the species is key to a $2.6 billion provincial tourism industry.