Strange as this will undoubtedly sound, my favorite smell is the unmistakable regurgitation of Speckled Trout.
Let me explain...
As a kayak fishing guide, finding the schools is half the battle. I then have to get them to bite the clients' offerings. Operating in the marshes of South Louisiana, the main target species are Speckled Trout, Redfish and Flounder.
Redfish are easy to find: Just look for roseau cane along the shoreline amongst the grasses. That cane requires a harder bottom than the common muck of this vast estuary, and the hardest bottoms around here are usually oyster beds. Find the cane and you've found the beds. Redfish are prolific over oyster beds.
Flounder, like Reds, are predictable. Deep holes/channels in Winter, then staging on sandy points with good current flow the rest of the year. Fish the eddying backside of these points with a light jig on the bottom. TwitchtwitchBAM. It's not rocket science...it's fishing. But there is an art to being successful day-in day-out.
That brings us to that ever-popular Speckled Trout. Except for the large sow females , they're a schooling species. As such, competition for food is inherent and we can use this to our advantage. I know where the lone sows hang out each season, but trophy trout fishing is a completely different matter. These schools, however, can move far distances over the course of a single day. To find them consistently...
...wait for it...
...Continually sample the marsh air for a distinct scent of
strawberries and cantaloupe.

Yep. Berries and melons. My favorite scent by far. Even in the produce section of my grocery, I can't help but think of fishing.
The feeding Trout will herd shoals of baitfish and shrimp, gorging themselves like Caligula. They then regurgitate the shells, carapaces and scales. This mass is accompanied by undigested fish oil which then rises through the water column. Upon breaking the surface that odd combination smells like, well, strawberries!
Detect the berry-melon scent, scan the horizon for the oily sheen, then paddle over and watch the clients catch their limit of fish in mere minutes.
Their cheeks hurt from grinning so much! And that gets my little outfit repeat customers, year after year.
Favorite smells: Strawberries and Cantaloupe.
Worst whiffs: Decaying human flesh.