It will be a very easy solution when one takes a less bureaucratic stance and be less hostile to foreign cultures: just mix the sauce with sea water and (really) slowly release it into the ocean. If Japan can release radioactive water into the ocean safely, I’m pretty sure you can do it with the fish+salt solution too. Yes, there is nothing in the fish sauce except these two ingredients.

Better though, take samples and test against food standards from countries where they actually produce and eat fish sauce. If the sauce is still good (could be due to the high salt content, not sure though), just let Ngo bottle it and sell the good stuff, internationally!