You are thinking on the right terms, regarding the pest species such as and common carp, tilapias and magurs. Mulley though is not a species that is actively cultivated. On the other hand it is native to our waters and therefore a part of the original water systems. It is mulley that in fact would also be keeping a lot of the pest species that have invaded these original water systems in check as they are a predatory fish. It is in fact possible that the mulley are on the increase as they get more of these invasive species to eat. It is nature's own system of pest control and you are destroying the medicine !!! Even though they might be plenty of those fish in that particular locality, it is definitely a fish which is on the decline in a lot of places such as Assam where i am from, especially due to OVERFISHING. There a good mulley is a prize rather that a pest, due the rarity of it. Big stocks of such fish (which you are lucky to have found), usually find their way into connected watersystems and are responsible for maintaining a healthy population not just in a 100 km's radius but far beyond that.
While fishing to kill and killing to eat is a saying that holds true for oneself, but not when 4 or 6 rods fish for 20 people. Two 3 kilo fish is enough to see a family of 4 or 5 people through two weeks. I know because i am a huge foody and love fish myself. And FYI i have also taken mulley home and will continue to do so, but just not in the quantities that far exceed MY household needs.
Anyway, i hope you and Dezz see some sense in what i say. But you are the elder and i cant tell you what to do or not to do, but its just my thought.
Tight lines and all the best.
As per what little I read it says this species is "Destructive to other more valuable food-fishes" and that it doubles up in 15 months and is only. However, it also states that "Lower risk - near threatened status in Western Ghats, India". It is not threatened due to less cultivation but more due to over harvesting.
And as I said Salim is definitely a matured human being to understand that we have to sustain the fishes so our generations can enjoy this sport as well. So to Salim, on a subtle note, take what you need not what you want as you know human wants are never ending :)
And when you say 25 kgs of wallago attu Do you mean you actually weighed the fish because I was wondering the appetite of all of the guys present there :)