Duck mussels

[Magnus.s]

There is a fresh water lake just next to my grandparents summer house (in Sweden). When I was a kid (25 years ago) I used to snorkel there for hours and hours.

This weekend I was back in the lake for the first time in ~5 years, and to my surprise there was Duck mussels [Anodonta anatina] every where. When I was a kid you could always find a few large one (10-15 cm) but now there was hundreds (+) of smaller (5-10cm) ones.

What I was wondering was if it possible to draw any conclusions about the conditions of the lake form these increasing numbers of mussels? It feels like it should be a good thing?

Thanks,
// Magnus;

[shinek]

Interesting question, could just be natural variations in population over time. Any population is fundamentally controlled by two variables, food availability and predation. More food = bigger population, more predators = smaller population and somewhere along those lines, a balance is established but there will always be some ebb and flow depending on local conditions.

Mussels are filter feeders and a significant increase in their population may imply an increase in their food source which could be due to any number of factors, some good, some not so good. For example, fertilizer run off can cause increases in algae and plankton growth which may result in an increase in the Mussel population. Similarly, some external factor may be reducing their natural predators, increased fishing, other pollutants etc.

You could try checking out local studies, either from the government wildlife type departments or perhaps local university biology faculty. They're the sort of people who carry out scientific analysis of this kind of data, rather than my speculation. Good luck!

Alternatively, just dive the lake and enjoy whatever you see down there. Lots of mussels, typically, means better visibility.

[hbh2oguard]

There is a fresh water lake just next to my grandparents summer house (in Sweden). When I was a kid (25 years ago) I used to snorkel there for hours and hours.

This weekend I was back in the lake for the first time in ~5 years, and to my surprise there was Duck mussels [Anodonta anatina] every where. When I was a kid you could always find a few large one (10-15 cm) but now there was hundreds (+) of smaller (5-10cm) ones.

What I was wondering was if it possible to draw any conclusions about the conditions of the lake form these increasing numbers of mussels? It feels like it should be a good thing?

Thanks,
// Magnus;

A similar event occurred here in Southern CA. There use to be huge clams, and tons of them. Then a major storm hit and they're gone. Now it's been quite a few years and there are just little tiny clams but none of the huge ones.

[Magnus.s]

Alternatively, just dive the lake and enjoy whatever you see down there.

I think I'll do just that

Thanks,
// Magnus;