Walleye Searchers 2023 Presentation

Hi everyone! Attached you can find a copy of the presentation I gave at the recent Walleye Searchers meeting February 6th in Rochester. As usual I have attempted to capture much of what I said or explained in the notes attached to each slide in the pdf document. In general populations of most game fish on Lake Pepin/Pool 4 seem to be in pretty good shape with near record numbers in some categories and no real trouble spots of note.

As always if anyone has any questions I can be reached via e-mail at [email protected] or by message here.

Thanks,

Nick

Attachments:

1. Walleye-Searchers-2023-Presentation-w-Notes-1.pdf
2. Walleye-Searchers-2023-Presentation-w-Notes.pdf

Sorry for duplicate file attachments.

Briefly scanning thru your comprehensive report one thing sticks out.
Why such strong year classes in 18 thru 21?
and why such a difference in walleye v sauger?

Hey Nick appreciate the data ! Had a good time meeting you at the ramp and talking to ya . Beggars cant be choosers but next year video it or live stream the presentation would be great !

Thanks for the question about year classes. First off I want to apologize for whatever happened to those figures when converting to pdf attached are jpegs of how they are supposed to look. That may make you less surprised by the results.

That being said water levels are one of the strong drivers for year class on Pool 4 with both Walleye and Sauger benefitting from a timely (typically mid April) flood pulse.

One of the differences is that walleye seem to do better when the high water is extended. This is likely due to their preferred spawning areas (at least in Pool 4) consisting of terrestrial vegetation that is inundated by floodwater. The longer that water stays around the more developed the fry can get in that relatively low flow area with ample food and cover from predators.

Sauger on the other hand seem to prefer channel borders. This means they can likely more consistently get good reproduction as floodwaters aren’t necessary to access their spawning area (but if high waters don’t occur they have to share this area with the Walleye), but fry hatched in the channel are potentially susceptible to being washed away in high flow conditions so previous studies indicate that a rapid drop in water levels post spawn benefits Sauger production.

Now that we have those basics for Pool 4 covered we can see that extremely high water levels in 2018 and 2019 definitely favored walleye. The hydrographs were not as good for Walleye in 2020 and 2021, but remember fish grow and mature fast in Pool 4 so many of those fish from 2018 will be spawning in 2020 and 2021. To many spawners can suppress production of a good year class (indeed we have some evidence of that in Pool 4), but my initial take is there were just more Walleyes out there in 2020 and 2021 that lead to better numbers.

The rapid drop in water levels is pretty apparent in the 2020 hydrograph (makes sense the Sauger spawn was good) and similarly the higher and more extended flood peak 2019 was bad for the Sauger year class. The hydrograph in 2018 had a double peak, though the drop is later than I would have thought would benefit Sauger production. I will follow up this post with some marked hydrographs to illustrate my points.

Attachments:

1. 

   Sauger-Year-Class-Strength-Pepin.jpg
   

2. 

   Walleye-Year-Class-Strength-Pepin.jpg
   

Thanks again for the presentation last week at the club meeting Nick. Its always a pleasure to have you speak to the club. Already looking forward to next year.

See attached for figures that show the hydrograph information I discussed in the previous post.

Attachments:

1. Walleye-and-Sauger-year-class-and-Hydrograph.pdf

Nick whats the craziest species youve netted so far ? Any indication of bighead/silver/asian carp ?

I haven’t seen anything too wild in the nets on Pool 4. During sampling American Eels that we usually get electrofishing are about the rarest. We have had a few Pacu caught by anglers (almost certainly from illegal aquarium releases) and while I was sampling in college we electrofished a blue and black Plecostomus on a river in Iowa (also almost certainly an aquarium release).

As far as Silver and Bighead Carp go. We know there was movement during the high water in 2019. We had one snagged by an angler near Red Wing that was entered into our creel and collected by our invasive carp staff. We have also taken part in several multiagency efforts to find and remove them called MUMs where MUM stands for Modified-Unified Method (see more about that here Modified-Unified Method (MUM) . To date other than the fish in the creel we have not captured a Silver or Bighead Carp in Pool 4 using our standard sampling gear. Most have come from commercial operations or targeted efforts by our Invasive Carp Team who are typically using methods similar to commercial anglers like large seines etc. If you have more specific questions about Invasive Carp I recommend contacting Grace Loppnow [email protected] the MN DNR Invasive Fish Consultant as she is likely to have a better overall perspective.

Appreciate the reply ! Thanks !

Nick have you seen many muskie in P4? i see you have one in your profile pick. i have heard rumors of some strays in P4 but is there any truth to that. a few years ago i hooked into a nice fish around the rush and i swear it was a muskie when it broke the surface. never did get it any closer after my line snapped?

eyeguy507 wrote:

Nick have you seen many muskie in P4? i see you have one in your profile pick. i have heard rumors of some strays in P4 but is there any truth to that. a few years ago i hooked into a nice fish around the rush and i swear it was a <strong class=”ido-tag-strong”>muskie when it broke the surface. never did get it any closer after my line snapped?

I’ve heard rumors of them being caught , makes sense as they could wash in from the Zumbro or Croix . I’d think they’d grow to record size with all the food in the system but who knows .

Couple years ago when the creel guys were asking baited questions to lower the limit I caught a muskie, that day Chris W. Boat also caught one per the creel guy. So yeah, they’re in there.

Nick, thanks for the info. And really appreciate you taking my questions a few weeks back. Be well man!

My profile photo is actually of a pike. The heaviest one I have ever sampled in fact and it was from Lake Pepin (42.5″ and 27.75lbs if I remember correctly) which made it heavier than a 48 incher I sampled once on the Canadian border.

As for Muskies in Pool 4 we see them occasionally. I have never sampled one in our gear, and every time I thought we had one electrofishing it turned out to be very large pike, but the commercial seines (particularly down at the bottom of the lake) occasionally sample them. SO far of the say 2 dozen or so I have had reported to me in the 11 years I have been on Pool 4 almost all of them have been ~30 inches long. Our best guess it they are primarily originating from stocking in the Chippewa by the WI DNR.

That being said we have had an occasional acoustically tagged Muskie from the St. Croix show up on our array and about 8-9 years back a very large muskie head was found in Pool 5 I believe so there are likely a few transient fish our there. I doubt that we have a breeding population in Pool 4, but if we ever stumble into a large one or numbers of them they will show up in my reports.