(warning to anybody coming after me: discussion of this piece includes necessary spoilers)
I’m a straightforward motherfucker, so as long as you’re ok with that, here goes.
The first 10 paragraphs, while interesting, are not relevant to the story. Not really. I think you could probably condense them down to a single paragraph, two at the most. Unless I’m missing something about the seal corpse, it is a mere distraction. Possibly you are attempting to use it as a form of foreshadowing, but if so I am too dim to make it out. Most of the description is lovely (not all, it gets a bit too adverby in spots), but all it does is slow down the lead in to the meat of the story.
The interaction between the boy and the man feels a bit thin. I think this is partly because the lead in is so long – you get this lengthy buildup and then all of a sudden you’re rushing along. It is also partly due to neither character being fleshed out. We need something about them, some mannerism or reference, to bring them to life a bit. In particular, the old man needs more meat on his bones – otherwise his death is no form of tragedy at all.
I think you telegraphed the ending a little too much – as soon as it was clear that the stick was a rib I knew what was going to happen. Not exactly how, but what. Still, I think the ending is good, creepy in a sort of ‘oh cool’ sort of way.