In the morning there was a big wind blowing and the waves were running high up on the beach and he was awake a long time before he remembered that his heart was broken.
There isn't any symbolysm. The sea is the sea. The old man is an old man. The boy is a boy and the fish is a fish. The shark are all sharks no better and no worse. All the symbolism that people say is shit. What goes beyond is what you see beyond when you know.