I posted the same thing on here one time, everyone thought I was crazy. Fish can adapt very fast when the situation arises.So these are caught in brackish water. Probably end up in the ocean as adults. However, science is fluid, its not concrete. Over years, not thousands of years, fish can adapt. There are crater lakes in the world with landlocked marine species, and it didn't happen over thousands of years. Lake Tal in the Phillipines have complete freshwater Caranx sp. that grow to 3 feet in size or more. Same with Lutjanus argentimaculatus in Australia.