The stern of the Benwood is the shallowest and most destroyed part of the ship. It's strewn all about and twisted metal and collapsed gunnels make great homes for the types of critters that like to hide under things.
This also seems to be the spot that the sargent majors lay those circular piles of purple eggs. They defend them by swimming at you very fast to try to scare you away, and have been known to run right into your mask, or nip at you quite freshly. It's very interesting to witness this instinctual behavior.