There is a chance that the black death could be included in the revision of the general shooting licence that is underway now until December,
It would be a good thing if anglers responded in enough numbers to make it count.
A reservoir in the midlands next to the A5 was restocked with 25,000 small carp after being drained for repairs and all the fish removed, no fishing was to be allowed to let the fish settle in and grow on a little.
After around 18 months a day was spent netting the whole reservoir to see how the fish were getting on prior to it opening again and British Waterways managed to locate just a handful of these stockies only to be informed by locals that around 20 cormorants were on the water 7 days a week happily eating everything.
I recommend you check your sums, pellet weight or muzzle velocity. A 16gr pellet at 780fps is 21.62 ft.lb
To be legal, a pellet travelling at 780fps would need to be less than 8.9gr and is likely to be .177.
Pellet dependent, I'd expect to see a muzzle velocity of less than 600fps for a sub 12 ft.lb .22 air rifle.
You can get them as a trial pack of 50, that's what I did, just to try them. Now I send for the tins of 200, a bit expensive but I've yet to find a better vermin pellet. They also take down Mink. By the way, the rifle is Co2 powered with 10 shot magazine.
And that fish is said to be a Carp, not Tench...though I have my doubts on it being a Carp, unless it's a strain I've not seen before.