Rideau Canal - Mystery Snails
Shells at the end of an inlet lead to a top-10 snail name and an elusive invasive species.
EPISODE NOTES
After returning from the Rideau Canal, I realized it would be really useful to have shells from these snails to shoot in order to put together this episode. But I hadn’t brought any back with me.
So on a trip to Ottawa a little while later, I spent a good portion of my time finding excuses to go to shorelines so I could prowl for snails, which turned out much more difficult than I was expecting.
Predictably, it was on the last day of my trip, in a park near where the Rideau River meets the Ottawa River via Rideau Falls, that we finally managed to find some - they’re the ones you see ‘in studio’ in this episode.
TRANSCRIPT
On the second morning of our Rideau trip, I went down to the end of a canal to catch what I could of the sunrise, and as I was waiting for the time lapse to run, I started to notice snail shells among the rocks. I collected them to pass the time and wound up with two piles.
Now they might look superficially similar, but it turns out these are two very different snails.
Over here, we have a modest little native gastropod, the marsh ramshorn snail. And it’s pretty obvious where they get that name, the flat coil of their shells looks a little like a ram’s horn.
I’m only mentioning that to contrast with these guys over here. An invasive species called the banded mystery snail - truly in the top 10 all-time great snail names.
But compared to the ramshorn, it’s certainly a little less obvious - even mysterious - where this snail’s name comes from. Except the ‘banded’ part.
The ‘mystery’ it refers to is this: these snails seem to appear out of nowhere. You have a couple in your tank one day, the next day: they’re all over the place.
It’s actually because they don’t lay eggs. The female snail gives live birth to fully formed babies, with shells. So if you’re expecting a whole snail life cycle, with eggs and larvae and soforth - like the ramshorn snail among many others - these snails seem to appear like magic. Hence: mystery snail.
The other mystery is how they got into the great lakes in the first place, because that also seemed like magic. Before 1931, no banded mystery snails in the Great Lakes, and then… presto. They could have been carried on boating equipment or a bait bucket… they’re also pretty popular for aquariums, so it’s possible this whole mess could have come from nothing more than careless aquarium dumps into the waterway.