i've just found Suicide Island and I'm currently reading that.
The jist of the tale is Japan decides that rather than keep it's suicidal people alive they will just get them to sign consent forms and dump them on a large island. this way they're not a drain on society.
so this cluster of people wake up on the island, realize what's happened and then they see two people not in their group kill themselves by flinging themselves from a high place, they see someone else attempt suicide but fail, just ended up a twisted antagonized mess of broken limbs.
this sufficiently freaks them all out because their selfishness didn't allow them to think about the mechanics of suicide, so now the people are on an island with no convenient food.
i'm only 3 chapters in so i expect it to turn Lord of the Flies pretty quickly. In fact so far in the capter I'm on, there's about to be a gang rape.
anyway, you can check it out at onemanga if it strikes your fancy.
personally I am looking for a good sports manga. maybe a baseball one.