In the Rifters Trilogy, is the Rifters' maximum survivable diving depth established?

The Rifters "Trilogy" comprises [Starfish](https://rads.stackoverflow.com/amzn/click/com/0765315963), [Maelstrom](https://rads.stackoverflow.com/amzn/click/com/0765320533), [Behemoth: B-Max](https://rads.stackoverflow.com/amzn/click/com/B00M64A670), and [Behemoth:Seppuku](https://rads.stackoverflow.com/amzn/click/com/B00M64A666) by Peter Watts.