A significant part of this length consisted of the tentacles. It weighed about a ton. The maximum size of a giant squid is probably around 60 feet, but it is possible that they grow larger. The sperm whale is probably the only predator of adult giant squid, although they are open to a larger number of predators when they are small. It is really not known how well or by what method a giant squid avoids sperm whales, but a sperm whale is such a huge animal that once it seizes the squid in its jaws, there is little the squid can do.
Giant squid have no gas spaces in their bodies.
Therefore there are no cavities to expand or compress as the pressure changes.