Big Green Lake Fishing Report – May 15th, 2019, Fishing in an Algae Bloom

Snot Grass (filamentous algae)

It’s Wednesday night bass league time again.  Every Wednesday night, the Big Sacks Bass Club runs a bass fishing league.  You have about three hours to catch the two largest keep able bass. This past Wednesday (5/15/2019) was on Big Green Lake.

We hit the lake early for some scouting.  Water temps were anywhere from 51 to 60 degrees, with the warmest water being on the eastern shore of the lake.  The wind had been blowing from the south and the west, so the majority of the warmer surface water was pushed to that side of the lake.  There was also distinct lack of healthy weeds in the lake. Instead, there are plenty of dying weeds and clumps of decomposing weeds also floating in the lake, which resulted in a a huge slimy algae bloom

A filamentous algae bloom

You know the slime, the thick filamentous pond algae that clings to your lures, line, and everything else.  This kept water visibility down from normal.  Why the algae bloom? The DNR sprayed Big Green Lake for weeds again.  (I wrote about the status of Big Green Lake in 2017) and after some investigation it turns out they are spraying the entire lake, in a multi-year treatment cycle, for invasive species of weeds. The treatment cycle should be done in the early 2020’s but until then, every spring we are going to be greeted by decomposing weeds, and an algae bloom. 

Considering how popular of a pleasure boating lake Big Green is, I cannot help but wonder if the lake association will keep spraying beyond the current treatment cycle just to appease the pleasure boaters.  I hope not, but I’ve seen other lakes continue that year in and year out, much to the detriment of the fisherman and fish population (Legend Lake in Menominee County by Shawano… I’m looking at you!!!!!)

Back to the fishing report….


  • Sunny
  • High 50’s
  • Moderate wind
  • Green stained water due to the algae bloom and weed die off. About a foot and half visibility
    • *NOTE – In green stained water, chartreuse colored baits really stand out and are easier to see that most colors
  • Water temps – 51 to 60 degrees

Sorry to say, but we didn’t do well, and many of the other teams didn’t either.  The 2 best winning fish combined for around 7.5 lbs by Dan Helmer. That is a low weight for Big Green Lake. A 2 fish limit of at least 8 lbs is common, and the winning 2 fish often top the scales around 10+ lbs. Several teams, my team included, failed to weigh a legal fish (14″ min).  Even with the water temperatures being for the most part in the mid 50’s, the fishing was slow and we struggled to find active fish.  Considering it’s the mid may it should be prime pre-spawn bass season, and we expected to find active fish in normal staging locations… that wasn’t the case.  We managed to pick off a few smaller males… mostly on reaction baits.  We had only one big bite on a slower technique (Neko Rig).  I think with the colder than normal spring, erratic weather, algae bloom, and lack of weeds has everything is a few weeks behind the normal spawn.  

Dan Helmer with his 2 winning fish at Big Green Lake (photo borrowed from the Big Sacks Bass Club Facebook page)

But… all was not a loss. We did find 2 prime pieces of isolated structure that we now have GPS waypoints for that will payoff for us on future trips. Both are classic pieces of isolated cover… and we lost a huge fish at the first spot.  (The big one that got away… kept me up that night thinking about it…  it’s 2 days later and I’m still thinking about that lost fish.)

In looking back, I wish we had fished faster and just covered more water in the 5′-15′ range looking for reaction bites instead of running between several staging locations looking for fish.

(I also wish I had written a similar report from our early trip to Big Green last year… because these were the exact same conditions we ran into and we struggled then.  We could have been better prepared this year. )

I’m sure this won’t be the last lake we encounter that has been sprayed for weeds and has a filamentous pond algae (AKA the slime) outbreak… so I’v been doing some research on how best to fish it and found a great video from the guys over at Tactical Bassin. (Pay attention around the 3 to 4 min mark where he talked about visibility during an outbreak) I hope you find it as helpful as I did.

Tight lines everyone!

Vincent Wondra

Vincent Wondra

Obsessed with fishing since a child. Vince loves to share his knowledge of the sport, while helping encourage selective harvest and protection of the resource. He shares fishing reports, tips, tricks, and more during his never ending quest to be a better fisherman. PRACTICE CPR: Catch. Picture. Release.