"Appears On Island Every 3rd Saturday"? this is not the case for everyone. please correct this misinfo.

100 points and you get a gold fish trophy

Prizes I've gotten:
Fish-print tee
Anchor statue
Fresh cooler
Fish Umbrella
Fishing-rod stand
Tackle bag
Fish print
Fish rug
Fish pochette
Fish-drying rack

At 100 pts you get a special gift that comes in the mail. I haven't checked that yet.

I was able to get 8 fish in 3 minutes, and so got 10 points. If you can get 8 each time, you'll have enough after each for swag. So far I've gotten an anchor statue, some fish wallpaper, a fishing shirt, a cooler like the one CJ has, and a tackle bag you can wear.

...Something I've been doing is getting 10 fish bait ready, starting the contest, then I just have to run down to the ocean and throw in bait, catch that fish, throw in bait, catch the next etc...

Here's my experience so far...
Once you have at least ten points, you can trade them for some "swag". If you get more than 3 fish, an extra 2 points are added on to your total at the end...