So it depends if Nook's is open. I got the gold nugget island last week, and had a bunch of scorpions when I got back. Nook's was closed, so I put it in my storage, and just waited until Flick came by today. Otherwise, I usually sell to Nook's the day I catch it.
There's about 4 minutes left. I have noticed that my game clock is a few seconds faster than other devices in the house that connect to the internet for times. So be careful, the price may drop between 152 and 216.