HBound,
I'm not sure I would fully trust the survey's determination that BG and LMB populations were low. They may be normal but if they are really low the weed problem may have something to do with that. I feel like there is a lot of information we are missing. But if you are to succeed, you are going to have recreate a young pond. This means space for fish to grow into. The BOW needs to be under capacity in order to put weight on existing fish. Controlling the weeds, if it stimulates bloom should help but harvest in your situation of 35 acres doesn't seem tenable to turn the tide. There is probably a ton of LMB in there and several times that weight of BG. It's going to feel like plugging a leak to only find a new one pops out. Now I speak strictly with regard to your goal of regularly catching 6lb + up to 12 lb LMB. If your are serious about this goal, you should consider other remedies.
The benefit of draining is that it concentrates the fish where you can cull easier, predator fish can find prey easier, and natural forces accelerate the mortality of the older fish. While the water is down .... the rooted aquatic vegetation on the now exposed bottom will die. Upon flooding, there is a lot of free space for the fish that remain to grow into. They will grow rapidly and a lot forage will be created. There are many examples of such strategies working very well to grow large LMB. A lake as large as yours can benefit from this strategy even though it makes very little sense for a 1 acre pond. If I had a lake that size I would want to be able to control the lake's level and I would design a system for doing that. With big LMB the goal, I would probably use this technique in lieu of stocking, feeding, and such simply from a cost/benefit standpoint. The level control system can greatly extend the life of your spillway and reduce its use. Something it seems the neighbors upstream are doing.
As for the dumping by the neighbor. If the they increased the flow without cause when you requested help then that wasn't very neighborly. But they may have been following a protocol in management or possibly just receiving more water. Being able to control your water level is something you need too, its a powerful management tool that every large BOW should have. Any BOW that is full has to shed water. In that sense, the neighbor isn't dumping fish nor are they dumping water. They can't hold it all and neither can you. The fishing in their BOW might be more like you remember the fishing in yours. When you think about from that perspective ... it is clear that their BOW isn't the reason yours is a shadow of its former self. That said, when controlling numbers of LMB to ensure fast grow to trophy sizes, it wouldn't take many recruits to make this goal more difficult and most certainly, beyond some threshold fish larger than 6 lbs might become improbable. I mentioned the influx of LMB recruits from above as a risk and it most certainly is when the goal for LMB ultimate weight is as high as you have set the bar.
With all that said. I do wish you luck with this. I will give you this fair warning. Small adjustments either through harvest or stockings will not probably work in BOW that size. It will be a lot fun catching and eating the fish but it will be like steer and a heifer. You will get no calf. You can spend tens of thousands of dollars on herbicides, feed, feeders, fish, and .... and still have a pond full of fish that are less than the size you desire. Enjoy this and as Dave in Texas says don't try to hide what your are spending on the lake from your wife!
Below is some information from the electro fishing and other observations.
On the day of sampling the lake was at full pool and the water had a visibility of approximately
46 inches. I measured total hardness and it was 19 ppm.
Fragrant water lily (Nymphaea odorants)
was the dominant emergent. Watershield (Brasenia schreberi) was also common while the
shoreline was vegetated with soft-stem bullrush (Scirpus validus). Coontail (Ceratophyllum
demersum) was the dominant submergent species.
During my sampling the overall abundance of fish was quite low. I collected 7 species, black
crappie, bluegill, largemouth bass, warmouth sunfish, lake chubsucker, golden shiner and chain
pickerel.
Largemouth bass were widespread in the lake although not abundant. Young of the year bass, spawned in 2021 were not detected in my
judgement. I suspect that they failed to survive their first year of life because of high predation
and intense competition for food resources.
Based on this
distribution about 94% of the lake has vegetation growing in it. The density of vegetation was
low to moderate, probably because it is early in the growing season.
