This one works on so many levels I love it: we have here your basic mythology gag involving mistaken identity between the Greek versus the Roman incarnation of the aquatic deity, juxtaposed with the double entendre in a caption between authorship and a local/Alaskan reference.
This particular panel also serves as an instance where another attempt at tweaking via Photoshop so as to adjust the elements into a better composition was called for. This can be seen below by comparing the scan of the line art on the right versus the panel on the left, which has considerable more visual breathing room - things aren't so compositionally cramped + the god is shifted in size , rotation and placement (ever so slightly brought up into the foreground with the angler).
So yeah, this is also a lesson in pole-vaulting over a
But it just goes to show you that what at first seems to be Olympian-caliber concerns are only tiny little bubbles in the champagne of the joke. Sometimes nobody really cares about the fine details about the glass okay? Use a mug.