At the risk of sounding like a boot-polisher, an excellent article, Sir. Some thoughts and enhancements…
Biologists are telling us that the zebra mussel is going to be soon replaced by a larger and more agressive species, the quagga mussel. That link has a good pic showing the difference. The jury is out whether this will be a good or bad thing, but it will certainly be a change and probably a rapid one.
I would like to take issue only with Cecil’s claim that the water color has changed due to the mussels. I have lived all my life on Lake Michigan and I really don’t notice a color change other than the daily/hourly ones attributed to sun, clouds, bottom composition, etc. I suspect the areas around Chicago have been cleared up largely by decreasing manmade pollution; my experience is in Door County, Wisconsin, where there is very little industrial activity and polluters, if any, have never been large. I can assure you that my neighbors never thought of our water as turbid, cloudy or “a bucket of sludge” except when a storm stirs things up.
I don’t dispute that the water has become clearer, but I doubt that that has changed the color. Sky/cloud reflections and bottom compositions are the greatest contributors to this, I believe.
BTW, Cladophora is pronounced clad-OFF-uh-ruh, and the problem with it is exactly as Cecil described, and no solution is yet in sight. Experts claim that the washed-up stuff on the shore represents only 1% of what is growing in the lake.
When I get home from work today, I’ll post some good pictures of beaches with the stuff. I have lots of 'em.
According to Indiana’s DNR, when the zebra mussel appears in a lake, the local redear sunfish go from eating anything that moves to eating only the “Zeeba Neighbors.” So far, nobody has taken the step of either putting the redear off limits for anglers or stocking lots more redears. What seems obvious to me must be a bad idea for some reason I don’t know about.
Although they’re not exactly the same animal, they usually are lumped together when people talk about the problems of Zebra mussels and the Lakes. I know that even very recent reports on the problems at power plants and water treatment facilities at the Lakes lump them into a broad terminology of “Zebra mussel”.
One thing that Cecil touched on only tangentially is the heavy metal toxicity. Years ago, Lake Erie was so fouled with pollutants, especially mercury, that it was ill-advised to have any contact with the water, and certainly no swimming. Now, the water is almost free of mercury, and swimming is no problem. But elements don’t just go away. Thanks to the zebra mussels, all of the mercury that was floating free in the water is now in the food chain. And since mercury is a bioaccumulant, anything that eats the zebra mussels will have even higher levels of mercury in its flesh, and anything that eats the things that eat the mussels will have higher levels yet, and so on. The net result is that, even though the water itself is now quite clean, you’d be extremely ill-advised to eat anything that came out of Erie.
If both species of mussel came from the Black Sea region, what are Black Sea-ers doing? Have they learned to cope? Does it have any natural enemies in that area?
I’m not suggesting we import an enemy to our enemy – Og knows that kind of scheme usually backfires (cf. Cane Toads) – I’m just asking.
Thanks to elfbabe for getting my post up during the day!
Here’s some data from the article I cited above, showing how the zebra mussels are on the run!
So we see that in Lake Michigan at least, the zebras are becoming uncommon.
Frankly I can’t tell the difference between zebra and quagga without looking really, really close. Which I don’t do.
It is freaky to have the beach at my home be littered with mussel shells. Back when I was a kid (late 50’s) thru the early 90’s, shells were just completely absent from our nice, sandy beach! How annoying.
Oh well, the alewives haven’t been so bad in recent decades.
Back in the '70s, the Asiatic clam, Corbicula fluminea, invaded the waters of the USA. The lower Sacramento River bottom was plated with the little shells of the clam. The upper Potomac River had thousands of clams per square meter covering the bottom. The Corbicula also filtered out huge quantities of algae (Cohen, R.R.H., Dresler, P.V., Philips, E.P. and Cory, R.L., 1984, The effect of the Asiatic clam, Corbicula fluminea on phytoplankton of the Potomac River, Maryland: Limnology and Oceanography 29(1): 170 - 180).
The Washington, D.C. government’s environmental department wanted to take credit for cleaning up the persistant blooms of algae by adding advanced treatment to the Blue Plains treatment plant, but evidence suggests the Corbicula was the primary agent of agae removal.
The Potomac Electric and Power Co. was spending a million dollars a year cleaning the Asian clam from their intake screens. Back flushing with chlorine, often effective to remove fouling organisms from those screens was not working on the clam. When stressed by the chlorine, they just clammed up.
Corbicula also was displacing native molluscs, like unionid clams. Seems like the Zebra mussel is taking over where the Corbicula left off.
Starting out by reading the Straight Dope kick-starts my weekend. Thanks, Straight Dope crew!
My understanding is that, in some places in Asia, the Asian clam, no bigger than a thumb nail, is fried and eaten like popcorn. I do not find it particularly tasted, but with some good, greasy deep frying, it might be palatable.
Also, Qadgop the Mercotan, I know what mercaptan is, but no Mercotan.
Isn’t Quagga the native name for marajuana in South Africa. Oh, I remember now, that’s Dagga.
My understanding is that, in some places in Asia, the Asian clam, no bigger than a thumb nail, is fried and eaten like popcorn. I do not find it particularly tasted, but with some good, greasy deep frying, it might be palatable.
Also, Qadgop the Mercotan, I know what mercaptan is, but not Mercotan.
Isn’t Quagga the native name for marijuana in South Africa. Oh, I remember now, that’s Dagga.
I read somewhere that they found a new way to kill them in intake vents. Instead of dissolving chlorine (or some other substance) in the water, it is put in pellets (of gel, I believe). The mussels eat them like food. I guess in this way the mussels take in more chlorine before putting up their defenses. The pellets dissolve after leaving the vents.
I knew about the prediction that Q’s would be taking over, but there was about a 10 year lag time between Z’s being numerous if you dived down in shallow rocky areas and the same objects washing up on my beach. Since my beach is all sand, and at least a 1/2 mile from any rocks, the mussels don’t attach here, just wash up when the animals inside die off and/or they detach from a hard surface. And after a storm, the shells are pulverized and not numerous, anyway.
So I assumed that there would be a similar delay with Q’s showing up here. Nevertheless, with the stats you quoted, I went down to the water’s edge a few minutes ago and examined carefully what I found. I had always assumed that the whiter shells were white because they had been bleached by the sun, but after picking up a handful of samples and looking closely at each, I have come to the conclusion that the whiter, larger ones are Quaggas and the smaller, darker ones are Zebras. My source of expert difference descriptions was this site I linked to earlier.
The diff sure is subtle. This is going to require a new article in our local newsletter, as all my neighbors have been assuming we are seeing Zebras, and I think we are all wrong.
On my beach, I would estimate the count ratio of Q:Z is 3:1. Since the Q’s look more durable, they may persist longer and be broken up by the waves less. They sure look more robust than the fragile Z’s.
I’d post a closeup picture, but my camera isn’t working well right now. I have the collection I made sorted into two piles, and think you can tell the difference.
Did you go swimming last weekend, musicat? The lake was rough, but the water was in the 70’s. We spent the weekend in the lake. Lots of mussels got washed up. Not so warm today, sadly.
We’re 7 or 8 miles from rocky beaches here, so the shells are more transient. But some days after a storm, one has to watch where one steps!
Didn’t go swimming, if you require 100% immersion, but the water in early to mid-September is usually about the warmest it gets, indeed, and great to wade in.
Also good to drink beer next to. Wear a sweater.
I probably won’t get a good chance to check underwater until next season, but I haven’t yet seen any evidence of Quaggas attaching to the sand bottom, at least in the swash zone. So the only thing we have to watch out for underwater is the hidden “holes” formed when we have extreme waves. Sand, gravel, mussels, etc., are never a problem for me on the shore; my feet are pretty tough and I never wear shoes on the beach (which is probably why they are so tough).
It’s certainly better than 15 years ago when we had to walk on piles of alewives, squishing eyeballs and sliding on slimy scales, to get in the water. I got a few tiny fish bones stuck in my feet those days. Mussel shells are nothing compared; they feel sharp, but I have yet to be cut by a single one.
