Zebra Mussels - Fishing before and after

[ThunderLund78]

While we all agree we don't want them in our lakes, they're becoming a reality in more MN lakes every year.  For those of you that have fished any infested water for a considerable time both before and after confirmed infestation, what changes have you noticed?  Obviously all lakes are react different to infestation; sometimes the zeebs don't take as well in certain lakes with lower fertility, etc.  Sometimes you hear about improved water clarity, with negligible impact to fishing, sometimes you hear about noticeable declines in baitfish and gamefish.  Are there any personal observations from any of you out there that have experience with waters pre/post infestation?

[Rick G]

Sofar, the only things I have noticed are an increase in line getting cut while fishing brush and rockpiles. We catch clumps of zeebs clinging to rocks and sticks now, where as just a few yrs back we had none. They do seem to breed rather quickly when conditions are right. On a positive note, the otters really seem to like to munch on zeebs. More than once I have seen them along the shorelines with a pile of tiny shells in front of them 

[tunrevir]

Forest Lake was just diagnosed as infested this year so too early to tell with regard to water quality and the associated problems that come along with zeebs.  Mille Lacs has had them for quite awhile and the DNR is blaming them in part for the increased clarity and possible decline of the walleye and perch fishery due to competition for plankton.  They may also be to blame for decreased tullibee numbers.  I have not seen an appreciable decline in the St. Croix but river systems tend to have alot more runoff continually washing through them.  From a fishing perspective, I have had crank baits fouled with zeebs when trolling on Mille lacs.  I think they will become a real headache for any lakeshore owners when they start colonizing docks and boatlifts.  I suggested to my parents that if they become to big of a problem in Forest that they think about trailering the pontoon for each outing and not put a dock or boatlift in the lake.  This may prevent issues with a dock or lift but could potentially lead to infestations in other bodies of water if the boat is dropped into other lakes and a sufficient drying out period has not occurred between outings.  As most of us know, water may sit in the motor, the bilge and live well in small amounts even after sitting out of the water and throw a little rain in the equation and the drying out period becomes prolonged.  Interesting days ahead for sure!

Tunrevir~

[BobT]

I can't help but think that the immediate impact of zebras is short-lived.  They flourish rather quickly at first because they have no real threat from predators and the food supply is almost endless.  Eventually they will eat themselves out of house and home and like any other species they will begin to decline until they establish a balance between the available food supply and their own numbers.  The lake's ecosystem will rebound at that time to some level.  What isn't known of course is what will that level be?  Unless we can find a way to remove them once they've become established, one of my concerns is that if we do too much to try to control it ourselves, we could upset the natural order of things and actually create more harm than good.  

[IronDioPriest]

Just from one fisherman's perspective (with no scientific knowledge of aquatic biology/ecosystems) I haven't noticed any real change to the fisheries that can be directly attributed to zeebs, other than clear water, and maybe deeper, healthier vegetation.

It seems reasonable to think that with less floating particulate matter in the water, deeper penetration of sunlight would enhance and expand weed growth in the littoral area of an infested lake. It follows that fish habitat would be enhanced as well.

Of course, that says nothing of the food chain. But all game species will orient to healthy weeds, so that seems like one possible net benefit to an infestation. Might as well try to find something good about the inevitable.

[BobT]

I might not be correct on this but I think one of the concerns is that in the process of cleaning a lake the zebras are feeding on what would normally be food for minnows and other small creatures and although the lake gets cleaner it also can be depleted to the point the other "native" fish species suffer for it.  By "native" I mean current accepted species.  

The concern that I have is that we are so focused on preventing zebras from getting established and trying to find ways to remove them once they are that I fear drastic action may come as a result which could in itself be more damaging than the zebras.  For example, it wasn't too long ago that an attempt was made to use chemicals in an effort toward cleaning up Lake Osakis.  Unfortunately, for whatever reason, a mistake was made that resulted in fish beginning to die off.  It became necessary to use more chemicals to counter-act the first chemicals.  

I don't know if there's any truth to this or not, but I heard once that part of the reason for Lake Osakis' high level of phosphorous can be traced back to the early 20th century.  In an attempt to improve the lake's fertility farmers were encouraged to spread manure on the ice in winter.  Sounds a bit far-fetched but to be honest, it wouldn't surprise me too much to learn that there is truth behind this.  

I also think about the forest tent caterpillar problem (army worms) and how we imported some fly species that would supposedly feed on the eggs of the caterpillars.  Unfortunately, the fly itself is a real nuisance and likes to bite.  

Another example would be the Asian lady beetles that most are familiar with.  These were imported in 1988 to counter the aphid populations.  But they are so aggressive they displace the native lady bugs, cause their own damage to plant life, and are prone to biting. 

 

[Tom7227]

This week's outdoor news has a bit of info from the Lake Doctor.  As BobT wrote there is some depletion of zooplankton due to the action of the zebs.  But Mr. McComas suggests that the loss may be offset by greater zooplankton production in the increased mass of weeds caused by the clearer water.

I live on Bald Eagle Lake in Ramsey County.  An alum treatment was done last year.  Prior to that the weed line was at 6-8 feet and the secchi disc was 3-4 feet max.  This year the weed line is 8-12 feet with dramatically thicker weeds and the secchi reading is 12-15 feet.  Mr. McComas has been a consultant to the local lake association for 15+ years.  When asked if the clearer water would impact fishing he said that it likely would because of the greater amount of cover.  Personal experience is that the weeds are making it tougher to fish, no opinion yet on whether it has caused an increase in numbers or size.

[ThunderLund78]

Interesting, Tom.  I'll have to read that article.  My outdoor news is still sitting on my table, I haven't had a chance to get into this week's issue, but I always enjoy reading McComas' colums

[gunner55]

Second or third year of Zeebs on the lake we are on & the weed line has moved from 10-11 fow to 14-15'. I have found weeds down to almost 30' this season & it was hard to find them much past 20 before. The lake assoc. just had their annual meeting & the person who monitors the water clarity reported he found it to be 26' this spring. It wasn't but about 1/2 of that before the Zeebs. That being said, I've had 1 of my better seasons, especially for quality fish(17-24 with a PB of 28 all C & R) but  I've been fishing deeper than usual. Much deeper( 20-35) than everybody else unless it is a overcast and/or windy day.

[Tom7227]

I misquoted the article.  The zebra mussels eat algae and so they compete with the zooplankton.  Fewer zooplankton interrupts the food chain that game fish rely on. 

[BobT]

I think the jury is still out on the true effects from zebra muscles in a lake.  I'm sure it will vary from lake to lake as well.  

 

[gunner55]

I think your local DNR biologist will probably tell you the same thing.

[MI Friend]

Michigan has had them for many years now.  Result in my opinion. On Lake Michigan not much impact as most species of trout/salmon are cold water critters.  I get most of the Lake Trout mid day, 80-110 ft down, mid summer.   Steelhead  down 15-30, about the same as years ago. As for the walleye fishery,  some impact!  We now find it difficult to get fish in day light hours.  Still there and can get some but not easy.  Saw many walleye guys go to the Bass fishing thing. Crappie and pan fish, have seen no difference, still in shallow water on the weeds.  Hope it give some  idea as to what might happen in MN.   Best to all.  Will be at Breezy Point on Aug. 28th then to Detroit Lakes for another week.  Normally do 4 weeks but the wife planned a trip and I had to just go with it.  Next year back to a month there. 

[papadarv]

Thanks @MI FRIEND for the bit of history in Michigan. Seems like long term Zebras did not have much effect in your neck of the woods. Back in 1986 the uproar on Eurasian Water Milfoil was much louder than the current concern for Zebras. Forecast of destroying fishing, boating and basically shutting down most lake activity never occurred. Not much is said today about EWM and 30 years later we still are catching plenty of fish and fishing pressure today is probably 10 times greater than it was in 86'. Science  came up with ways to manage the milfoil, they will most likely do the same for Zebra. Just a thought.

[ANYFISH2]

Our fisheries will always adjust to some kind of equalibrium, fishermen and lake users will adjust as well.  Our lakes will survive just about anything we throw at them, might change some, but no doom and gloom.

[John Mickish]

I fish a fair amount of Zebra infested lakes when I travel East. Here is my observation, and it's not all doom and gloom but things change.

Water clarity will increase, making longer leaders, planer boards and longer rods key in getting the bait/lure away from the boat.

The forage that Walleyes eat may change, so new some new patterns may develop. The way you used to do it may not work anymore.

Line choices will be important. Flouro is tough but it sinks, so it puts itself in harms way. Mono floats above the zebs but it cuts easy. Retie your braid often.

If you touch bottom, bring it up and check it, there is a good chance your "zeebed up".

Finally, you will lose more stuff than you did before the zebs got there.