Last week I put out some beer traps (old beer in a deep bowl) to catch the slugs and snails in the Mound- and to my surprise the next morning, along with a few drowned slugs, were at least half a dozen dead prawns-cooked by the beer!
Admitably the prawns were little, finger nail clipping size....
In order to prove I'm not crazy, the next night I put out a bowl of sea water, and sure enough, the next morning I had collected three live prawns (now swimming in the fish tank)
I think that the seaweed I've been using has prawn eggs or hatchlings, and during the night they've jumped into the bowl...
I am certainly the first person in the world to sprout prawns in a permaculturemound