Here's a theory, and i'm by no means saying people shouldn't keep fish, i keep fish myself. And i am probably massively over simplifying this but check this out.
1 Mackerel can produce 90,000 eggs. Lets say 2% of them for argument sake survive to spawn again.
If you were to keep 300 fish, that would be 300 fish that cant spawn that year, that would be;
300 x (90,000) = 27,000,000 eggs that wont be produced in year one.
and
27,000,000 x 2% = 540,000 fish that wont spawn in year 3.
using the same maths, in year 3 those 540,000 fish could have produced 48,600,000,000 eggs thats 972,000,000 fish that could have made it to spawning age in year 5. If you follow this through to year 35 you end up with. 6,557,734,679,216,090,000,000,000,000,000,000,000,000,000,000,000,000,000,000 fish that never lived because 300 fish were taken by one angler. Multiply this by the number of anglers and number of piers....
Now this isnt intended to have a pop at anyone keeping loads of fish, like i said to start with, i keep fish myself and im sure there's massive holes in my logic but an interesting thought while your having your lunch time cuppa.
