Using the indefinite article after the definite article with the same object

Question

I came across an ESL short story with an unusual usage of articles:

Jake was a keen fisherman and at the weekends he often took his boat out to the middle of the lake to relax and recover from the hustle and bustle of the working week. One day, Jake was sitting in his boat, enjoying the tranquility of the place. The sun was shining and he was listening to the gentle lapping of the water around his boat. He noticed a woman walking along by the side of a lake. The woman stopped and called out, ‘Hey! You! Are you thinking out there?’...(the full story)

Could anybody help me to understand the usage of the articles with the word "lake" in the passage? Isn't that the same "lake" in the both sentences? As I thought we should use "the" with the object which has already been mentioned. Maybe there is another rule in this case?

Answer 1

You're right: these are a bit anomalous.

The first "the" is a convention of narrative. Even though the lake has not been mentioned before, starting a narrative with a definite phrase like that helps build the sense that we are hearing just one part of a longer story: "the lake" isn't one we know anything about, but it is the one that Jake would refer to as "the lake".

The "a" is odd: it can only mean that she was walking by a different lake; but that doesn't make sense either, so, as Lambie says, I think it is a mistake.