edited

Notes:
1) A couple of the descriptions in your opening line are a little awkward. When you describe his hoodie as "rough," do you mean the texture? Or that it's old/worn out? If it's the latter I'd choose a different word. And I'm unclear on what you mean by coon-eye tan. If you're just talking about his eyes, I don't think the word tan should be there, but if you're talking about his skin coon-eye doesn't really work. (Is this a really common phrase I just don't know about? If so, ignore me). This is nitpicky but since it's the very first thing your readers will see I'd consider rewording.
2) In the anecdote from Luis Muniz: the hickey joke is cute the first time, but I wouldn't include two quotes saying the same thing. I recommend ending Luis' after "pull as hard as we could."
3) You mention that it’s almost the end of mackerel season twice: once in part I and again in part III, so cut one of those
4) I’m hesitant about the drug cartel comparison in Part IV. I find it funny, but it has a negative connotation. I wouldn’t cut it straight away, but maybe get a second opinion from someone? 
5) In line 72, you use the phrase “his love for the sea” twice in one paragraph 
6) His work is described as backbreaking twice, once in part I, and once in a quote in part V (it’s a distinct enough word that I think you should only use it once in a piece of this length)
7) In part V, you mention skin cancer as one of the “symptoms” of his addiction to the sea – does he have skin cancer? has he had it? or are you just naming it as a potential risk?  

AP style and grammar looks good. I like the tone and the descriptive details; it was very easy to picture different scenes and follow the narrative.