In reply to aln:
Not in my experience. It smells mainly of fish, but not quite, maybe a little salty or tangy. Easily identified because of the fish scales that can make it look as if someone tried to roll a turd in glitter, and because it will always be on top of a rock or tree stump, as otters, like all mustelids, use their faeces for territorial marking.
Thus, the martens that live next to my house always choose to shit precisely onto the stubby antenna on the roof of my car. I don't eve bother removing it any more other than by driving. I guess that my weekly commuting long distance, with the car otherwise parked in prime marten territory at either end, drives them into a marking frenzy...
CB