Well, Friendlies did try the tiger prawns in their raft beds. They found that they didn't manage to harvest enough of them to make them really salable. I mean can you really market a product that you only manage to harvest about one meal for a family a year? Keep in mind that you probably only get to raise about one prawn per meter squared of raft.
I don't know how hard it really is to get the aquaculture permit but seems to me you would have to get inspected and I believe they want the site fenced to keep people from releasing the animals into the wild. It would cost probably something like $100 a year. Miami Aquaculture and other places I know of will require proof of the permit before selling the prawns to you.
Now I don't know if there are any other edible smaller shrimp species that might be native but it seems to me that might be a better way to go but I don't know really.
I don't think the number of prawns one can grow is really related to water quality, it is more due to space as the creatures are territorial.
Now the shallow raft beds make a fab place to grow them as it's a dual purpose use of the space since the rafts are also growing the veggies but one would really need an extensive amount of beds to grow enough prawns to really make them commercially viable and at that point the operation will be so huge on the veggie side that the prawns would still be such a small sideline that they probably wouldn't bother with them.
I actually like the idea since it adds more diversity but I kinda doubt many "commercial" ventures would find it all that profitable. I think it would be great for a large home or community size system but I doubt many of those in the USA would be able to get the prawns (due to the permitting) or they will be in a cooler climate and might not grow as big in a season. What one could grow would probably still only be enough for one special meal or something. But those are the sort of celebratory things that add real spice to life sometimes.
k edmonds said:
TCLynx is right about being able to grow enough. From what I have read in a University of Nebraska study on prawns, is that you could expect to raise 10-22 pounds of prawns per 1000 gallons of water annually. The pricing they quoted is $6-10 per pound(early 2000's). I talked to an extension educator last week who said this study is no longer being conducted. Would like to know if AP would or could change those ratios. ??