What do giant squids eat?

Thoughts on that giant squid some Japs caught on tape off the Marianas:

The sperm whale eats giant squids.
But what does the giant squid eat to become that giant?
Giant eels? Did you know eels never stop growing?
And what does the giant eel eat? Methane hydrate? Or is that what he leaves behind after having eaten?

And after the New Englishers and later Onassis killed about 95% of all sperm whales, was there an explosion of the giant squid population? Did they turn to canibalism? Or did they eat all the giant eels and died of starvation?

Questions, questions, questions …
(Like: How old is the water? And how does it come into existence?)