[lapsis_beeftech]

Alas, (unless you mod the game) you do not get shells from turtles you bring on embark or import through trade; they are already processed and ready to eat, no shell included. You do not even get a shell when you buy mussels!

[bombcar]

Interesting, maybe I was bringing live turtles? Can't recall if that was possible.

[lapsis_beeftech]

Pond turtles are considered fish and live fish is not available to bring on embark. Since the only source for shells is fishing it is somewhat common to mod the game to make shell acquisition easier, you might have had one of those running.