Need some help doing this right up front. I have a state permit to stock our established, natural 40 acre lake with walleye, perch and fatheads. This is a windswept alkaline central North Dakota lake with sand/rock hard bottom which averages about 14' deep -- contour is a deep bowl. No inlet or outlet, spring fed. It is a fertile lake (surrounded by pasture)with limited weed growth and good populations of large invertebrates (freshwater shrimp). At this time it does not contain any fish or minnows. NoDak game and fish has stocked other area lakes with walleye, perch, n. pike and BG.

Our goal is to produce a recreational walleye fishery. Period. I had planned to introduce walleye fry and try a bi-annual stocking of same. I don't expect to have walleye recruitment through spawning but not out of the question. I would guess this lake will freeze out every 8-10 years so I may have to repeat this process several times. I'm most concerned about the timing of introducing perch or fatheads. If I plant walleye fingerlings next spring, should I wait a year before introducing perch/fatheads? See any problems with the plan? I hope to avoid the expense of planting walleye fingerlings if possible.

Thanks in advance for any advice you can provide.

Hi PSRguy. There is no book on what you are trying to do. Thus, there may be several ways to get to the same goal. Let me toss some suggestions at you.

If this was me, I would indeed introduce adult fathead minnows next spring. They won't start to reproduce (probably starting when water gets to the 60s F) until after the walleye fry have already grown to a big enough size to eat the fathead fry. So, the adult fatheads you stock won't be enough to really compete with the newly stocked walleye fry.

I really don't know what to stock for fathead minnows. What would be the cost of stocking at least a gallon per acre (40 gallons?). I'm just guessing, but that should be plenty to get the reproduction started. In a study we did in Minnesota, we could essentially wipe out fathead minnow reproduction with a walleye fry stocking. Whether you buy the fatheads or collect them yourself, be absolutely certain that you know what you are stocking. DON'T let any small black bullheads or common carp get into your lake with the stocking! Keep them out or you can really hurt your walleye production in the long run.

I'd stock the walleye fry at a rate of at least 1,000/acre (40,000 fry). Some people go up to 2,000 per acre (or even more). I don't feel strongly about this, but remember that more walleyes can mean slower growth. However, that really is more influenced by the survival rate than the stocking rate, I believe. I do know that you should not go under 1,000.

I always worry about the yellow perch getting out of control before you establish predators. To be honest, I'm probably more conservative than I should be. I think I'd suggest the following. If you are stocking yellow perch fingerlings (age 0 fish), then they could go in next spring (or early summer). They won't reproduce in 2005, but they probably will have fantastic growth rates on the conditions you described, and may reproduce at age 1 (2006). [If not, they definitely will reproduce at age 2.] That way, the walleyes will have something to eat that year. I'd also do a second walleye fry stocking in 2006, just to make sure the predators get off to a good start. You probably won't get as much survival on the second stocking, and the older walleyes will be happy to feed on the newly stocked walleyes. However, I think it would be safer to have at least some walleyes in the second year class. Once per two year stockings may be just fine after that, but I'd start with a couple of walleye year classes if you plan to have perch in the lake.

If you plan to stock adult yellow perch, then I would wait until spring 2006. Stock them pre-spawn, and get them producing so the walleye will have prey at that time.

Walleye fry stockings do not work in all waters. However, if your lake is fish-less now, and as productive as you say, I think it should work.

Hope this helps! As I said, there probably are other alternatives, but this is what I would do.

Dave

PSRguy,

What do you mean by, 'I would guess this lake will freze out every 8-10 years...'?? Do you think you will have a winterkill due to low oxygen levels?

Russ

Thanks for the advice Dave.It's very helpful. I worry about perch stocking due to the potential for a population explosion if the walleyes don't take -- which I guess would make establishing walleyes thru subsequent stocking pretty tough (with fry out of the question).

Russ: Yes, I think it will freeze out periodically due to low oxygen levels. We have had "open winters" recently with very little snow cover but every now and then we get a tough winter and lots of the white stuff. We actually also have over 20 natural ponds on site -- most in the 3-8 ft deep category (1-15 acres), some with 12-14 foot dugout holes. None of them have fish/minnows in them and as a result are excellent for waterfowl production and rearing due to the high number of inverts. One concern I have about stocking fatheads is the chance for them to be transported to our other ponds (by waterfowl movement)and crashing the invert populations, so I was leaning toward a perch stocking for forage on the big lake. If they got into the other ponds they would nearly certainly winter kill each year. In general our acreage is managed for waterfowl production, so I need to protect the inverts in our other waters.

PSRguy: Given your last thoughts, what are the chances that you could find an adult yellow perch broodstock for introduction?

Here is a revised thought. You could stock walleye fry in spring of 2005. Barring any unforeseen event, they probably should make it as no other fish are now present. I’d expect lots of zooplankton for early survival of fry, and the age-0 walleyes can really grow on the large invertebrates (such as those freshwater shrimp). They may prefer small fish as prey, but you can bet that they’ll feed on the big invertebrates. You could do a little seining (I assume that would be legal if you have permission to stock privately owned fish in a private water?), and then make sure you have first-year survival on the walleyes. Then, you would know that it would be OK to make another walleye fry stocking in 2006, and then add pre-spawn adult yellow perch in late April or early May. Again, this is very subjective, but we often try for 20 adult panfish per acre of water when stocking smaller waters. However, I’m sure you could get by with less than 800 adult yellow perch.

If walleyes do not survive from the 2005 fry stocking, you might have to try fingerlings in 2006. Cross your fingers, and hope not. Again, you’ve got a pretty good situation for 2005 fry survival, so the odds are in your favor.

You're obviously knowledgeable, given your concerns over the fathead minnows and waterfowl populations. Yes, indeed – if the fatheads are unchecked, they can really knock back the invertebrates. Also, they tolerate lower dissolved oxygen than just about any other fish species. They are tough that way! The walleyes can really knock them back, but you’re right – why risk them getting into smaller waters where the fatheads may survive tough winter conditions that would kill all predator fish.

For the long run, I really think you need a prey fish present in your lake. Which is more risk -- fatheads or yellow perch? I think the perch will do you more long-term good, especially if you really expect 8-10 years between winterkills. You should have harvestable size walleyes after 2-3 growing seasons, and they do grow faster on a good supply of prey fish than on a good supply of invertebrates. The risk is that they can get out of control if sufficient walleyes are not present. Fatheads are much easier for walleyes to control, and that in fact is often the down side. Given abundant walleyes, fatheads can nearly disappear from a lake.

Where in central ND are you located? North, south, or middle?

Dave

We're right in the middle of the state -- about 70 miles north of Bismarck. What you've suggested may be the safest bet -- confirm that the fry took before introducing a second class year and a prey species in 2006. There would be no problem seining to check. The more I think about it the more I'm leaning toward perch as a forage base (due to the "accidental transplant" concerns laid out earlier) -- my concern then was whether the fry would do okay on inverts for their first year or year and a half -- sounds like they would. I'm in no hurry to produce catchable walleyes.

Sounds good, PSR.

Yes, the walleyes will do just fine the first year on abundant invertebrates. As I said, walleyes typically grow a little faster with fish as prey. However, with plenty of inverts, such as this newly stocked water body will have, they will undoubtedly be plump that first year.

I grew up in Mandan, and so that was why I was asking about your location.

Keep us updated as you progress through your plan.

Dave

I read one study on walleye diets where they found that chirnomids were the most commonly consumed food, but drum were number one by biomass consumed.

Aren't perch populations cyclical? I was under the impresion that they have large year classes every 5 or 6 years, and that the large year class surpresses the following year classes?

What kind of survial do walleye fry have in a fish less lake? 50%? 10%? 5%?

Is it possible to raise walleye fry in a net pen untill they reach 3"-6", and then release them?

Ty—here are some thoughts on your questions and comments.

“I read one study on walleye diets where they found that chirnomids were the most commonly consumed food, but drum were number one by biomass consumed.” Many, many walleye populations do a lot of feeding on invertebrates. Usually, the bigger the better, so they really got on something like a big Hexagenia mayfly hatch. When given a choice in laboratory studies, walleyes of all sizes will select fish prey (assuming it is the correct size) over invertebrates. I'm not surprised by your reference on chironomids (midges or bloodworms). We've had estimates of up to 40 million chironomids per acre of lake bottom in some eastern SD natural lakes. The yellow perch really feed on them!

”Aren't perch populations cyclical? I was under the impresion that they have large year classes every 5 or 6 years, and that the large year class surpresses the following year classes?” I prefer to use the word erratic rather than cyclical. Cycles mean a regular pattern of up and down, as you indicated. Yellow perch are not on any type of standard cycle. Often, not always, a strong year class can suppress the next one. We see that effect more often in walleyes than perch, but again, it’s “not always.” In SD natural lakes, we actually see some perch populations with pretty darn consistent year-class strength. They tend to be in the “nicer” lakes with submergent vegetation. They also tend to be higher density and slower growing. In shallow, windswept SD natural lakes with limited vegetation, the yellow perch year-class strength tends to be VERY erratic. Overall perch density tends to be low, except for those occasional strong year classes, and these lakes typically have very fast perch growth. The 13-14 inch whoppers often are only 5 or 6 years old. It sounds like PSR has a lake that might fall into this second category.

”What kind of survial do walleye fry have in a fish less lake? 50%? 10%? 5%?” I’d say my best answer here would be “yes.” Walleye fry in a fishless lake can have very high survival, up to and maybe even exceeding (rare) your 50% level. If it’s a cold, late spring and no zooplankton populations have yet begun to develop, then even in a fishless lake, survival can be low (down to 0% in a few cases).

”Is it possible to raise walleye fry in a net pen untill they reach 3"-6", and then release them?” My first thought was that walleye fry are so small (6 mm), and that you’d need a fine mesh size to hold them. I’m not sure how well that would work out in the world of wind and waves.

Dave