St John's Island used to be absolutely filled with cats.
Here's a video on it.
NTU Cat Management Network placed the cat figure at around 100-120 back in 2016.
But even then, issues such as keeping the cat population at bay had been bandied around.
And it turns out, that has been ridiculously successful.
According to St. John's Island Marine Laboratory, Singapore's only offshore research facility, there are significantly less cats now.
How much less?
There are only 16 cats left apparently.
In their post, they gave a few reasons for the dramatic decline in the feline population.https://mothership.sg/2018/09/st-john-islands-six-cats-bedok-quarrel/
Needless to say, don't take cats off the island.
So if you are intending on taking that 30-minute ferry ride over to St. John's Island perhaps over the long-ish weekend, do tamper your expectations.
Here is a horrifying read while you're on the ferry.
Do take note that St. John's isn't nearly flushed with rubbish bins as what Singaporeans might be used to, so do refrain from throwing rubbish there, and from over-feeding the cat population.
All 16 of them.
Image from NTU Cat Management Network and Singapore Island Cruises