I think the comparison to chub etc is true to a point, I can see the argument. But there is a difference in the biological make up of the fish. (Ok, at this point, I concede I'm not a scientist and don't have the knowledge in depth to get into a deep debate. But, there is a biological difference).
Regarding other single species, then surely it is the role of their groups etc to fight their corner. The fact that the barbel is well represented, and its case is fought for, by the Barbel Society and lots of well known individuals, is a credit to them. There is nothing stopping other groups from doing their bit. That can't be used as an argument against those whose cause is the protection of the barbel.
The point about farm reared fish, I raised in the article. When barbel are reared in this way, extra oxygenation is required. When put in the stillwater, that artificial situation is no longer present. Therefore the barbel is being placed into an alien environment.
At the end of the day, whatever point of view we have, it has to be based on facts. It's like the close season. Some say we should have it because 'I like to get the decorating done'. Now, I'm not making comment here on the issue of the close season. Just stating that if that is the only argument we have, then it's not really based on anything solid. The same with barbel in stillwaters. In the article I put forward my argument, which I felt was based on good solid facts, rather than circumstantial evidence.