Make use of those Festivals that occur on the beach. Since time doesn't pass, and you don't expend energy you can fish without worry.

1 - Bring your basket!
2 - Fish for the large fish, and fill your basket up. Max out your carry capacity by putting 8 more fish in your rucksack.
3 - Toss aside any garbage. You can always confess to littering later!

Your profit for a day's worth of fishing will be 7600G.