> He ate it does not necessarily imply he ate it all.

But it implies it.

> I ate chili last night, but that doesn't mean I ate all the chili.

That's a bit different isn't as you are referring to a general unquantified food ( chili ) as opposed to a quantified amount of food ( one whole salmon ). What if someone gave you a bowl of chili and you ate it. Most people would assume you ate it all. Because it's a singular item like a whole salmon. Someone game me a bag of chips and I ate it. "All" is implied. Someone gave me a hershey's bar and I ate it. Most would assume they ate it all.

Also, you are missing my point. My point is that most people don't appreciate how big salmon actually are and also how expensive they are. I didn't realize how big they got until someone gave me a whole salmon. My intention wasn't to start a petty semantic argument.

Hopefully a professional chimes in but I believe it does imply that he ate it all. Your example isn't one to one because you refer to it as "I ate chili" instead of "I ate it". Same way people wouldn't be confused if he had said, "He ate Salmon that night but" .

Similar examples: I painted it last night. (Painted a painting) I beat it last night. (Beat a game) I ran it last year. (Ran a marathon)

"Where's the chili?" "Oh, I ate it last night, sorry." (Ate the chili)

"Mmm, this chili is good, isn't it?" "Sure is, I had some last night." (Ate some of the chili)