With the death of orca Tilikum, Professor Philip Hoare, of the University of Southampton, argues the case for the end of whale and dolphin captivity.

On January 6, a 36-year-old bull killer whale named Tilikum died in Florida, "surrounded by trainers, care staff and veterinarians", according to the solemn, obituary-style announcement published by his owner.

Tilikum was, in fact, a celebrity. A star performer among the orca (as killer whales are known) at Orlando's famous SeaWorld theme park, he was also the world-renowned subject of an award-winning documentary, Blackfish, which has been credited with the dramatic decline in the fortune of such venues.

The film, which has been seen worldwide, showed the orca to be a highly intelligent and emotionally sensitive creature, condemned to a desperate existence in captivity with ultimately far-reaching tragic consequences. For Tilikum was also a real killer, implicated in the vicious deaths of three individuals.

As a boy growing up in the 60s and 70s, I was obsessed with cetaceans, the group of mammals that includes whales, dolphins and porpoises. Orca in particular fascinated me, with their glossy black and white markings, so sleek and streamlined.

They had a magical quality, invested with power, grace and beauty and yet capable of great violence, tearing their prey - salmon, tuna, seals and even other whales - apart with their large teeth. I saw them as supreme emperors of the sea.

Once, my two younger sisters and I persuaded our parents to take us to Windsor Safari Park where, at last, I could see orca and dolphins up close. There, in a concrete tank, barely bigger than a municipal swimming pool, a trio of dolphins went through their paces, jumping through hoops and balancing balls on their noses. Their reward? A dead fish from a bucket.