From a piece about SeaWorld (subscription maybe required):

The first Sea World opened in San Diego in 1964. It was the brainchild of four college friends who originally planned it to be little more than a restaurant with some aquatic viewing areas. Featuring dolphin shows as the main attraction, the park was popular from the start. But when the owners purchased the original Shamu in 1965 for $70,000 and began displaying her, revenues soared. Eventually Sea World would open locations in Florida, Ohio and Texas, and orcas came to be the parks’ mainstay. Sea World is zealous in defense of its use of orcas for understandable commercial reasons: Mr. Kirby cites figures suggesting that orcas account 70% of the parks’ revenues.

Huh. I’ve been to three different SeaWorlds and have absolutely no recollection of seeing Killer Whales. I had no idea it was that central to the business. I was always more interested in the dolphins (which killer whales apparently are a type of, but I mean dolphins-dolphins). Or maybe it was that the Killer Whale shows were too crowded, thus explaining both how important they are to Sea World and why I never saw them.

Anyhow, the piece is about a book about how it’s wrong to keep killer whales in captivity. It apparently makes a pretty good case, if it has Jon Last convinced.