You could also try running the game at 1/2 speed for a bit. They'll gather more fish then they can eat and you can get a bit of a stockpile going.

the people will get the berry bush back after long time

I too had a "random island event". I am sooo happy when I see them. Although I did notice during the game, even while picking crops and fishing, that my berrybush limit kept growing. The first game I played in demo, my berry bush depleted. But I had just earned enough tech points to learn to farm!! YAY!! I Love my Village!!xxx