I wonder if the survivor crew has antivenin on exile island for the highly toxic yellow-lipped sea kraits?

Answer 1

I am sure that the crew is prepared for all possible scenarios. Although the sea kraite is highly venomous they are mainly nocturnal and feed mainly on eels and such. Most sea snakes are not aggressive. They are rear fanged snakes and somewhat clumsy on land

Answer 2

I'll bet they never thought of it. Perhaps you should call the show and let the unit producer know.