Acting Commander Zee's Personal Log:
Slogs are such a vital Grog industry they were even mentioned in the Encyclopedia Galactica.

Each season, female slogs give birth to millions of eel-like slog larva, many more in fact than the environment could ever sustain. Grogs have harvested these larva as a food source since the beginning of their recorded history. They also select a few each season, based on strength and behavior, and allow them to mature... which if I remember correctly takes a few years and a lot of mud...

When a mature slog emerges from the mud it is fed and raised by Grogs, and with proper training they become beasts of burden and heavy transportation for the Grogs thanks to thick and leathery moth-like wings that can propel them through the ooze seas, like a manta ray, and much faster than most other native life forms...

... and now, I'm about to ride one...