Swan Mussel Reproduction Life Cycle

[heliart]

I've a wildlife pond I built last July, and it's been going rather well since.
I "seeded" the pond with a couple of scoops of mud/sludge/gravel from two local sources when I first got it going, and it has plenty of plants (although it's looking a little sparce at the moment).

Anyhow, I was amazed late last year when I was clearing the dreaded blanket weed from the bottom, that I had a swan mussel - only a small one, perhaps 8mm across. I heard that these hardly ever survive in ponds with still water, so didn’t expect too much.

Anyhow, today, I was clearing a little more blanket week from the very bottom of the pond that's preventing the lily getting started. Sorting though the blanket weed and returning all the life (there's a lot of life in there), I found 2 or 3 tiny tiny swan mussels - size must of been 1 to 2 mm across.
I guess it means they are getting something from the pond, and are starting to establish perhaps, but I can't find much info about their life cycle.

Cheers.

[The Woodman]

There are male and female Swan Mussels, some other bivalves are hermaphrodites.

The fertilised eggs are stored inside the female during the winter, I think, until they develop into glochidia, a free swimming larval stage with a short "tail".

These glochidia become detached from the parent and find their way into the gill structures of fish where they attach themselves to live as parasites for a few weeks.

They transform into tiny swan mussels and drop off their hosts into the mud to live happily ever after.

I have some images of Freshwater Pearl Mussel glochidia attached to salmon parr which I'll dig out and attach if I can find them.