Marineland of the Pacific switch
According to a pdf document Ceta Base has dug up, April 9th, 1970 was the day when Marineland of the Pacific had their animals switch tanks. They now had three killer whales (Orky 2, described as 5800 pounds, Corky at 4000 pounds, and little Patches at 1125 pounds), and they were moved to the main tank (which was renamed the Killer Whale Coliseum), while the dolphins and pilot whales were moved to the old killer whale pool.
In the first two photos, it's Orky being moved and lowered into the new tank, and in the third, it's Bubbles (our Bubbles who passed away last year) being moved out of the big tank.
The document says Bubbles was moved along with two other pilot whales (Bimbo was released before this), two bottlenose dolphins and four "striped" dolphins (they were not actually what we today call striped dolphins, but lags, Pacific white-sided dolphins). Since they don't mention Swifty, it seems she died before this. (And it adds up with my previous assumption, Swifty died some time in 1970.)
What's strange is that they also specifically only mention three killer whales, while databases I've seen said Corky 1 died in late 1970, and of course, Corky 2 came in late 1969. So is this article speaking of Corky 2, and Corky 1 was perhaps already deceased?
They also don't mention Kenny, and he died in 1972. Perhaps it was Corky 1 who was moved, and Corky 2 and Kenny were in another pool (remember, Orky 2 and Corky 1 were caught together in 1968. Corky 2 came with Patches and Kenny in 1969.) This is all terribly confusing.
The last photo above of three whales, is Corky 1 - very recognizeable - Patches, and Orky 2, which makes this theory more likely. But still, why wasn't Corky 2 and Kenny with them? Kenny was the last killer whale to die before Orky and Corky were alone.
https://www.newspapers.com/clip/12210904/marineland_pacific_orky_corky/