Astrosaurs: The Seas of Doom: 3 by Stephen Cole
Captain Teggs is no ordinary dinosaur - he's an astrosaur! On the incredible spaceship DSS Sauropod, along with his faithful crew, Gypsy, Arx and Iggy, Teggs rights wrongs, fights evil and eats a lot of grass! Teggs and his crew have been sent to a watery planet where a very large and very scary monster has been attacking a local fish factory. When Teggs and Gipsy travel down to the bottom of the sea to check out the monster, they come under attack themselves - and end up in the company of a rather strange creature with amnesia...Will they manage to find their way back to the surface?