First off, sorry for crashing the guy's forum. If you stick around long enough, you'll see that we tend to not really pay strict attention to the men's and women's distinction.
Anyway, my first thought was that your post reminded me that I've seen some articles, etc. about the swimmer's body fat mystery...that despite the exertion and calories expended, swimmers have a higher body fat percentage than most other athletes and AFAIK
no one's explained it with certainty. But it's not something that I've really dug into, so maybe someone else has some more insight or knowledge.
That being said, maybe swapping in some "land-based" cardio, and increasing your weight work, might get you the results you're looking for.