Sterilising cats is not the goal
Someone wrote in to say that they wanted to know if sterilising all the cats would lead to there being no more cats in Singapore, and hence whether killing the cats might actually be better, because the remainder would be allowed to reproduce. The person said they did not want to see a day where there were no more cats.
The thing is - sterilising cats is not the be all and end all. Saving lives is. I explained that once the cat is sterilised, it cannot reproduce. It would however live out the rest of its life without being killed ideally.
If at some point, we find the number of cats has dropped to the point where they are not reproducing, we will gladly stop sterilising. It's estimated you probably need to 90% of the ENTIRE cat population to reach this level. The remaining 10% will then reproduce enough to just keep the population constant and manageable. Of course, you need to keep an eye on that 10% or they'll reproduce enough again to cause overpopulation.
However this is all conjecture for we're far, far from this aim. 35 cats are still being killed every day and we have a long way to go before we can start thinking of stopping sterilisation.