# Weed mowers? Negative impact on the fishery?



## BASmead (Jan 11, 2008)

Hey folks, i would love to get some educated input on this. Not sure if this is the appropriate forum for this because of the size of the impoundment but here goes. 

My family has a spot on a 150ish acre lake in S.Mich. I've been blessed to fish it my whole life and it has always been a pretty exceptional bass fishery. It has, as long as i can remember, been a very weedy lake. It features 5 deep holes interspersed between large weedy shallow flats. The popular theory is that it is getting more and more choked out each year.

This past summer some of the residents chipped in and hired a guy for a ridiculous sum of money to come and mow the shallows. Actually, it was mid-september, which seemed like a strange time to me, as i'm confident these weeds will be back full force next summer. I've never seen this technology, it appeared to be some manner of hulking floating combine. It sucked up all my beloved weed mats and dumped them at several points on the shoreline. 

My first reaction when i went out and fished after the mow was positive, as it was much easier on my trolling motor. Unfortunately, over the rest of the fall i noticed the fishing was much much weaker. Now, granted, it could have been me. All fishermen go through slumps, but i gotta say, i know this lake confidently. I never found a proper fall bite this year, and not for lack of tryin'. I have always hit the fall bite in the past. Could be just the natural cycle of the lake, but my friends and i had a pretty decent summer. Is it ridiculous to think that we could have lost fish that were holed up in that vegetation? I would like to think that big bass are interested in self preservation enough to vacate a weedmat that's being assaulted by loud machinery, but i don't know... i do know for a fact that big ones reside in the thick stuff at times, as i've taken quite a few out of those very mats with soft plastic through the years.

Anybody have any similar experience or any experience at all with floating mowers? Thoughts? Only way i'll know for sure i spose is to go dig through the piles with a pitchfork lookin' for old one eye lulu that i caught when she was a 4 lber, i'd know her smile anywhere. Was hopin' to catch her when she's a 6... Great spot for jetskiers now though.


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## peple of the perch (Sep 13, 2004)

The mow the weeds at punderson, which is a very small 450 acre weedy lake. It seems like the fishing is ruined after they do the mowing there too. I think it does have a negative impact on the fishing. Mowing completely changed the environment.


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## ChrisB (May 13, 2004)

Michigan huh? Heard them and Indiana were trying this. It's a direct way of aquatic plant removal called mechanical harvesting. Fall is a good time to harvest as the plants and weeds are fully grown and uproot easier. Always a few problems with non-chemical treatments though, the biggest is that plants always find ways to grow back. In a few years the weeds will be back just as bad. I agree with your argument about removing them. You literally take out an entire eco system in itself removing weeds like that. Think of all of the spawns of batifish and insects that occur in that structure. Weed beds are also a mecha for trophy largemouths. You will suck out fish too when you harvest with that sort of machine. Not many, but it's going to happen. Odds are the bass moved out to other structure systems. Hate to say it but the lake isn't going to be the same for a while. Those pockets in weed beds are honey holes. Shoot me a pm and I'll walk you through placing artificial structures. It could help if your fishing there a lot.


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## [email protected] (Feb 29, 2008)

We run into the issue of conflicting interests a lot in this industry. Most fisherman understand the importance of aquatic vegetation; cleaning the water, adding oxygen, supplying cover for forage fish and conversely feeding grounds for the predators, etc. However, most home owners that live on a body of water place more emphasis on ascetically pleasing views, snag-free boating, etc. It is often hard to find a good middle ground between the two. 
I highly doubt that there was significant mortality caused from the actual equipment. Mechanical harvest of vegetation is a viable option for chemical free control. Any control method has its downfalls though. This method is expensive and labor intensive. Also, depending on the species of plant, you can expect a quick regeneration of the weed beds through the still viable roots/rhizomes and the bank of seeds that these plants have put out over the years. Some species will reproduce through fragmentation; any part of the plant that is not harvested can sprout in new locations, effectively increasing the weed infestation. 
The removal of structure/weed beds can have a negative affect on a fishery for multiple reasons, BUT too much structure can also have a negative impact. I hypothesize that the removal of the weed beds this fall resulted in an abundance of available forage fish for the predators because the forage had reduced cover to evade the predators. Therefore, the bass had ample food to keep them fat and happy and they just watched the lures swim by, just a hypothesis. 
It would be interesting to look at actual data from pre- and post- weed harvest, but without long term data it is hard to say what overall impact this will have on the fishery. I recommend that you take part in future discussions about management of the lake so the fishermans views are well represented. I would suspect that in a season or two you will be back to flipping your soft plastic through the weeds looking for one-eyed lulu.


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## [email protected] (Dec 22, 2006)

Lucas pretty much hit it on the head. I was thinking the same thing about the forage not having a place to hide making them easy targets. The good thing about the weed cutter is that it physically removes the weeds from the water. This is better than just killing them where they break down and rob oxygen then turn into fertilizer for the next round of weeds but as lucas said, it really depends on the weed they are harvesting and the circumstances as it may just spread the weed(s) around from fragments. It also seems like when you take out one weed and it doesn't grow back, another quickly fills the niche and you run the risk that it may be worse than the one you were trying to eliminate.

They did the weed harvest thing at Kiser but they seemed to do it in a grid pattern rather than complete removal. It seemed to make sense but I think it was met with a fair amount of negativity from fisherman. I can't say for sure if it helped or hurt fishing but it didn't take long for the lilies to fill back in.


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## BASmead (Jan 11, 2008)

Hey thanks for the great insight. I hadn't thought of it, but i'd guess it is far preferable to chemical treatment. Lucas, that's a pretty good theory about the bait being easy pickins'. Kinda like accidentally dumping a whole bag of dog food in fido's dish making him too bloated to chase rabbits. Do you think that could result in some predator/prey imbalance? Or perhaps it could be a good thing to thin out the baitfish once in awhile. There certainly has never seemed to be a shortage, just based on the bait i see cruising the shallows and the generally fat build of the pigs. Anyway, thanks for the thoughts folks...


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## nicogizmo911 (Jul 25, 2012)

Peple of the Perch is exactly right about Punderson Lake. I have been fishing the Lake my whole life for bass. Most recently, they have been spraying copper sulfate and have had that mechanical weed monster in there. The bass fishing fell to nothing since the weed monster came. I am very disheartened over this and I am wondering if a letter to the powers that be would do any good. The weeds at Punderson is the bass's main structure and cover. It was a huge mistake to disturb the ecosystem there. And Copper Sulfate is toxic to the fish at certain levels. There is no doubt in my mind this adversely effects the bass and the bass fishing.


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## Lundy (Apr 5, 2004)

nicogizmo911 said:


> Peple of the Perch is exactly right about Punderson Lake. I have been fishing the Lake my whole life for bass. Most recently, they have been spraying copper sulfate and have had that mechanical weed monster in there. The bass fishing fell to nothing since the weed monster came. I am very disheartened over this and I am wondering if a letter to the powers that be would do any good. The weeds at Punderson is the bass's main structure and cover. It was a huge mistake to disturb the ecosystem there. And Copper Sulfate is toxic to the fish at certain levels. There is no doubt in my mind this adversely effects the bass and the bass fishing.


It may change the mood of the bass and how they relate with their newly redesigned environment but they are in fact still there in the lake. They didn't decide to move to a new lake because their weeds have been cut or killed

Unless the dosage of copper sulfate was such that it killed so much vegetation at one time that the dying plants created an oxygen depletion that resulted in a large scale fish kill.

The weed removal should not have effected the existing fish population at all except for maybe the forage base that is more susceptible to being eaten with less hiding spots. The fish will adapt and the fishermen will need to also.


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## nicogizmo911 (Jul 25, 2012)

Dear Lundy:

I hope you are right and I was hoping you are. Going to give it the college try closer to the full moon next week and hopefully we will get some much needed rain. But there is no doubt in my mind, all the chemicals and "weed eating" affected the bass. No doubt they did not leave and there are still weeds and lilly pads and they should be back. Thanks for the insight. Nico


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## [email protected] (Dec 22, 2006)

I think Lundy is right on. I've noticed that after reducing weeds that bass don't bite as well. I think this is because they can get at the forage much easier. It doesn't take them long to get hungry again though.

Chelated copper liquid is what is used mostly and is very safe, safe for potable water in fact with no swimming or use restrictions. The only thing it is not safe for is carp and trout...and algae of course.

I have had several first hand experiences where, upon arriving to a lake that the locals say the DNR did this or that and fishing isn't any good because of it and they haven't been catching anything. Then a few hours later, I have a limit in the boat. After these events, it seems to me that the fish that were once patrolling the edges of weeds or sitting in pockets are now patrolling the places where weeds were removed or have moved off to deeper structure.


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