UF, I think the problem comes with your idea in the same area farmers have been running into for at least the last generation. Let's look a little more recent at the catfish industry all across the South. As many know that catfish farms are drying up down here, farmers are draining the ponds and planting corn. Thereby reducing domestic grown catfish, and encouraging more imported muddy cats from overseas. Seriously, next time you are at the store go flip a package of frozen fish over and see where it came from. Swai until recently was being marketed as 'catfish' and a suit broke out as this was harming what was left of the US farmer's cat crop. I am getting off topic though.
The US cat farmer is tilling em in for corn, as corn pays more. Catfish have a very low market now as imports can be done so much cheaper. In aquaculture, regardless of prawn, shrimp, catfish, etc. We lack the means to cost effectively compete with imports. Even though we can prove our fish are healthier, and don't retain the muddy tastes.
Your chance at making this work, is not through a processing plant, or a broker....and those are rare for this stuff now as they are having a hard time making any money.
Your best bet is what's called 'farm gate sales', mom and pop diners, and a handfull of smaller restaurants. Your ability to provide a year round, constant and consistant crop is what will make the difference.
My prawns for instance have a market, at several times what the imports are because I can deliver mine ALIVE. Let's see China do that! This is extremely important as shrimp/prawn meat breaks down very quickly once they are dead, and the delicate flesh loses a lot of it pallatability.

People pay a premium for healthier, fresher, domestic grown. BUT the market isn't big enough at these inflated prices to make a living on by itself, and I am not year round production yet. What's stopping me is the temperatures. I can't sustain constant temps, year round, cost effectively yet.
This is what has led to my interests with the geothermal that was referance in other threads.

But $4K for my apprenticeship for that, is a bit steap right now when income is dropping all around, and cost of living is going up. So for now, that dream is on the back burner.