Invasives and the effects on lakes

[Doctor J]

I hope this one hasn't been beaten to death before. My question is, with the inevitability of invasive species affecting lakes (zebra mussles, milfoil, etc), how much do we truly know about what the effects on lake quality will be? I get that zebras cut your feet when wading, and clog up water intakes. I have seen what a mess milfoil can be. Do we know what the effect on fishing quality has been on lakes that have been infected for a while?

I am all for prevening spread of invasives, but is it truly doom and gloom for our fisheries? Not trying to be controversial, just wondering if anyone has any good data to quote.

[goblueM]

given that lakes are complex systems and we only ever can have a snapshot of fish population estimates and size structure,and that many factors influence population dynamics, pinpointing the effects of invasives on fishing is mighty tough.

and even then, impacts of invasives might be positive for some fish and negative for others

[Huey]

I hope the spread of invasives is slowed as much as possible.

I do what I can; pick weeds from the trailer, pull plugs/drain boat, dump bait buckets on shore, etc., but I have to admit that I'm getting tired of being lectured by college interns at the boat ramps. It seems like evey other time that I pull my boat, I end up stopping as I'm cleaning weeds off the trailer so I can listen to the DNR or lake assoc. person tell that I should clean the weeds off the trailer?!

[Capt. H (Ret.)]

I think the invasive species problem is a real problem to deal with. I am not sure we can stop it but I really don't mind the interns at the ramp. There doing what they have to do and I just keep cleaning while they're giving their speal. Besides, every once in a while you get a looker which makes it more enjoyable!!!!!!!!!!!!!!!!!!!!

[Nick Kuhn]

Most invasive weeds are resource hogs and clear up the water some (except curly leaf). Zebra muscles also clean up the water. They will be overabundant until selection favors fish/insects that can consume the larvae/weeds. There's an invasive snail in our lake. Pumpkinseeds eat them. You'd swear every pumpkinseed in our lake was full of eggs with how fat they are. I imagine for a short while the same will be true in other lakes, until the population stabilizes and natives adapt to compete with the invasive.

[TurnUpTheFishing]

Zebra muscles filter out plankton which clears up water, also takes out a lot of food in the bottom of the food chain required for minnows and fry. They also kill native clams/muscles.

[BobT]

Zebra muscles filter out plankton which clears up water, also takes out a lot of food in the bottom of the food chain required for minnows and fry. They also kill native clams/muscles.

The question though is all this necessarily bad? So the natives are displaced. Sounds familiar to me.

[goblueM]

Bob, the issue he's talking about is zebra mussels sequestering limited food resources

they eat the plankton, which is the base of the food chain in some systems. Less plankton = less small baitfish and less game fish fry = less game fish

[bobbymalone]

might be a bit narrow minded to think of the spread of invasives in terms of fishing quality.

[Doctor J]

These points lead back to my question. It makes sense that if you disrupt the foodchain the biology of the lake will suffer. Have we seen this yet? Fisherman target milfoil beds for bass and crappies (edges). Mille Lacs and Lake Erie are incredible fisheries that seem to be as good as ever, yet have zebras and invasive weeds. Is it too early to tell on these lakes, or could we be wringing our hands over something that might not be as disasterous as we all think? It just seems that invasives will continue to spread, even with our best efforts. Swimming and boating are not pleasant with the zebras or milfoil, or curlyleaf, but what does the data show for fishing and fish population health?

[Doctor J]

I agree bobbymalone. Nobody wants them to spread. But as a fishing topic I think its an interesting topic.

[mainbutter]

Interestingly, anecdotal fishing evidence points towards zebra mussels making for very large pumpkinseed sunfish. Apparently they eat zebra mussels. The only two zebra-mussel lakes I have targeted panfish out of in the past five years had HUGE pumpkinseeds in them, particularly compared to the bluegills.

[Stick500]

the OP Dr. J is asking the million dollar question.

I don't think even fishery biologists can agree on the answer at this point.

For all our sake, I sure hope all the gloom and doomers are wrong and our fisheries survive.

As an avid snorkeler, I welcome having clearer water (like I hear it used to be before all the shore development and runoff problems at our lakes).

[mainbutter]

Stick, I quite enjoy some of the benefits of zebra-mussel lakes. I'm glad there are non zebra-mussel lakes, and we should do our best to keep it that way, but they are not the end of the world. They DO make for smaller and fewer fish in general.

For example, when they are present, they replace much of the forage for whitefish. Luckily whitefish can and do eat zebra mussels, but their growth on a zebra-mussel diet is stunted.

Many invasives have their pluses. Bass fishermen certainly target milfoil at times of the year with great success.

However, I do not enjoy ANY of the benefits of mass silver-carp infestations. Beyond one afternoon for the novelty of it, I wouldn't even enjoy netting them out of the air.

[pulleye16]

All these invasive species came from somewhere. Instead of "re-inventing the wheel", how do the lakes do where these invasive species aren't invasive?

I bet some research will show that they survive just fine. We are very lucky that nature can adapt to changes better then humans can.

[Sonicrunch]

All these invasive species came from somewhere. Instead of "re-inventing the wheel", how do the lakes do where these invasive species aren't invasive?

I bet some research will show that they survive just fine. We are very lucky that nature can adapt to changes better then humans can.

You are correct in that eventually, a balance will come to be. However, if that balance wipes out the walleye... well, I'm sure we would all reject that.