Interesting tidbit on Leech Lake walleye population

[Carp-fisher]

A very good friend of mine is in the fisheries biology program at the University of Minnesota. He is participating in a study that examines the stomach contents of Leech Lake cormorants collected from 2002 till today. According to him, the comorants have virtually no walleye in their stomachs, but rather a variety of minnow species. Evidently the data is pointing to a naturally cyclical walleye population that occurs because of the weather changes.

[Skunked-Rookie]

Personally I find it hard to believe that a predatory bird would take the time to distinguish between game fish and minnows when they are hungry, or even have a preference. I also know people who live there and have come up along side of the birds when they are on fish and have found dead Walleyes, some as large as 11''(they put their find in the freezer and showed me).

Lets just say that the birds majority of food is not walleye but minnows, it is already known that the birds eat about 1lb of fish/minnows a day so that would definetly have a harsh impact on gamefish food supply with the former population of birds being somewhere around 10,000.

If you have ever been to leech lake at night in rocky shallow areas you will notice it is infested with the rusty crayfish. The rusty crayfish is very aggressive I have caught them in 30ft of water and brought them all the way up to the surface without them letting go of your bait. I have also caught them on daredevils, they don't let go of those either. The rusty crayfish have also been accused of ruining cabbage beds and other vegatation by acting like lawnmowers destroying habitat in WS lakes. The impact of the rusty crayfish is not exactly known on leech but can definetly fit into the equation.

Also there had previously never been a slot limit on Leech, and now for the past (2-3yrs can't remember exactly) a slot has been implemented.

To say that a naturally cyclical walleye population that occurs because of the weather changes is was has impacted the population is not only premature but ignorant.

[Carp-fisher]

Quote:

---

Personally I find it hard to believe that a predatory bird would take the time to distinguish between game fish and minnows when they are hungry, or even have a preference. I also know people who live there and have come up along side of the birds when they are on fish and have found dead Walleyes, some as large as 11''(they put their find in the freezer and showed me).

Lets just say that the birds majority of food is not walleye but minnows, it is already known that the birds eat about 1lb of fish/minnows a day so that would definetly have a harsh impact on gamefish food supply with the former population of birds being somewhere around 10,000.

If you have ever been to leech lake at night in rocky shallow areas you will notice it is infested with the rusty crayfish. The rusty crayfish is very aggressive I have caught them in 30ft of water and brought them all the way up to the surface without them letting go of your bait. I have also caught them on daredevils, they don't let go of those either. The rusty crayfish have also been accused of ruining cabbage beds and other vegatation by acting like lawnmowers destroying habitat in WS lakes. The impact of the rusty crayfish is not exactly known on leech but can definetly fit into the equation.

Also there had previously never been a slot limit on Leech, and now for the past (2-3yrs can't remember exactly) a slot has been implemented.

To say that a naturally cyclical walleye population that occurs because of the weather changes is was has impacted the population is not only premature but ignorant.

---

I'm not going to call the fisheries biology department of the University of Minnesota ignorant. Evidently they've examined the stomachs of hundreds of Leech Lake comorants since 2002 (my buddy has personally done many) and the walleyes just aren't there. I thought the birds were to blame too, but he won't budge on the issue.

[Otter]

When you run a stomach contents survey after the walleye population has been decimated, you probably won't find a lot of walleyes in their stomachs!

[Carp-fisher]

Quote:

---

When you run a stomach contents survey after the walleye population has been decimated, you probably won't find a lot of walleyes in their stomachs!

---

That was my comeback, but he rejected it saying that the stomach data has been tracked over several years.

[Otter]

I watched Leech EXTREMELY closely for a substantial number of years, because I had planned to build a home on the lake. Prior to the cormorants some years were not as good as others, but I never had a horrible year. Fishing quality declined quickly in direct proportion to the increase of cormorants. People who have fished the lake for 50 years told me it was the worst that they have ever seen. This wasn't just a down cycle, it was a crash. The DNR has a history of analyzing the fox's stomach long after the henhouse is empty. In my opinion the walleye population had been pretty well whacked by 2002, so I wouldn't be surprised if they didn't find many walleyes that year as well as subsequent years. 2002 is the year that I decided to build elsewhere.

[Skunked-Rookie]

Quote:

---

I'm not going to call the fisheries biology department of the University of Minnesota ignorant.

---

You don't have to call them ignorant, I already did and I stand by that, if they think examining birds stomachs and not finding walleye means that a naturally cyclical walleye population occurs because of the weather changes.

---

Quote:

---

Evidently they've examined the stomachs of hundreds of Leech Lake comorants since 2002 (my buddy has personally done many) and the walleyes just aren't there.

I thought the birds were to blame too, but he won't budge on the issue.

---

Evidently you didn't read my thread through, I never said "the reason for the decimated walleye population is the comorants" I did give you three different possibilities with the birds being one of them. Now that dosen't mean I'm saying the birds are directly at fault, but I think it is undeniable that they are part of the equation of a number of different things that has affected the Walleye population.

[Otter]

It's that time between open water fishing and ice fishing again, so I knew it was only a matter of time before the cormorants would rear their ugly heads. Opinion on this seems to be clearly divided between people who have seen a flock of 500-1000 cormorants slaughtering a school of fish (like me) and those who haven't. It's an ugly sight that I hope to never see again. Fortunately, I think they at least reduced the population before they spread significantly to other lakes. I see a few on occasion, but not significant numbers, and I hope it stays that way. Let's all just hope that Leech recovers to what it used to be, whatever the reason for the decline.

[Carp-fisher]

Quote:

---

It's that time between open water fishing and ice fishing again, so I knew it was only a matter of time before the cormorants would rear their ugly heads. Opinion on this seems to be clearly divided between people who have seen a flock of 500-1000 cormorants slaughtering a school of fish (like me) and those who haven't. It's an ugly sight that I hope to never see again. Fortunately, I think they at least reduced the population before they spread significantly to other lakes. I see a few on occasion, but not significant numbers, and I hope it stays that way. Let's all just hope that Leech recovers to what it used to be, whatever the reason for the decline.

---

Cheers to that. I'm not totally convinced of what my friend at the U has concluded. The DNR officially takes the view that the birds have had a detremental on the walleye population.

[solbes]

Interesting info. It does stand to reason that they will see less walleyes if the population has declined. I do think the birds have had an impact, but I don't really believe it's 100% of the problem.

The good news is that the walleyes seems to be making at least a small comeback. Did anyone see the Star Trib article on Sunday about Leech? The last two years have strong walleye year classes. They said they should be 7" for this year's hatch and 12" for last year's hatch.

With the cormorant control and the slot I believe the lake will make a comeback. While I'm not on Leech, our lake place is only 9 miles to the west, so I'm getting excited to hear news like this.

[Otter]

I saw the article - gill net catches increased from 4.9 to 7.1. Any improvement is good news, but that number is still historically low. Perch population is also on the rise, another plus. I just hope people don't harvest too many fish before it recovers - the lake is still at risk.

[sdstatekid]

I think a pretty easy way to control the cormorat population would be to alow waterfowl hunters to shoot them. Then you wouldn't have to pay sharpshooters to come in and kill em and you would be saving walleyes, other gamefish, and the minnows they that they feed on not only on leech but all other lakes as well.

[Scott M]

Otter,

How do you know that 7.1 is still historically low for the lake? Is that on the internet somewhere? If it is I'd love to have a look at it. Imagine what the catches will be in the next couple years...Those YOYs and Yearlings don't recruit well to the gillnets and we'll be talking about huge catches.

My question, and maybe it is rhetorical, is how long will we continue to shoot cormorants? This is costing a lot of money, and can we really do this in the name of walleye?

BTW, to the original poster, the jars that I looked at with stomach contents were something like 95% perch, not minnows. Minnows would be quite an investment of time and energy for little payout for a foraging cormie....

[Bobb-o]

taken from the DNR survey of Leech Lake:

Walleye: The 2005 catch of walleye per experimental gill net set was 4.9, which is below the 1983-2005 average of 7.3 walleye per set. This relatively low gill net catch is due to limited recruitment since the 1997 year class. Historically, catch rates have ranged from 4.6 walleye/set (1993) to 13.4 walleye/set (1988). Walleye sampled in experimental gill nets ranged in length from 6.6 to 26.0 inches with an average length of 17.8 inches. Catch rates were higher in western bays (6.8 walleye/set) than in the main lake (3.4 walleye/set).

Due to concerns regarding the lack of recruitment in recent years, additional sampling was conducted to assess the 2005 walleye year class this field season. The catch rate for standard trawling stations was 247 young-of-the-year (YOY) walleye per hour, nearly two times the long-term average catch rate (124/hour). Night electrofishing catch rates in the main lake are encouraging. Through five hours of on-time electrofishing, the catch rate was 57 YOY walleye/hour. YOY walleye average sizes throughout the summer and early fall has been at or above average. Walleye sampled in mid-September averaged 6.7 inches in length.

[Otter]

Quote:

---

Otter,

How do you know that 7.1 is still historically low for the lake? Is that on the internet somewhere? If it is I'd love to have a look at it.

---

The info that Bobb-o provided in the post above is what I look at. Every year I read the DNR report for lakes that I have an interest in. Bigger lakes get sampled every year, smaller lakes less often. It's not holy grail, because some years netting is more or less successful than others due to weather or other factors. Also some lakes are easier to sample than others, but overall it is a pretty good indicator of fish population. Google mn lakefinder dnr if you want to check it out. Unfortunately, they usually don't post results to the internet until August the following year.

[Big Julie]

Any updates on the cormorant harvest; how many are left etc?

[USDA3]

http://www.llojibwe.com/llojibwe/pdfs/Cormorant%20management%20and%20research%20on%20Leech%20Lake%202006%20color%20final.pdf

This is an update from 2006.

[daddyducker]

You can't hack up the Do Nothing Regeime (DNR) too bad. Look at what they did to the Dead Sea(Mille Lacs). A couple years ago you couldn't have bought a walleye out there, not even from the Ojibwe, but now...WOW! It's hot. Say what you want, but the thinning of cormys and the slot; giuve it a couple of more years and Leech will be the place to go once again.

I agree with everyone's thoughts on this matter.

I have worked the bait industry for years and can tell you that cormy's SUCK!! But they are fun to shoot! I had a permit from the DNR in case anyone is wondering.

They are bad for business, and in numbers can wipe out some serious crop. The worst is; they bite alot in half and let it float/sink.

I don't think that they are the main problem, but with numbers where they were I think it is good the DNR did what they did. Rusty crayfish...maybe.

Cyclic runs, and weather...maybe, but not as likely. Global warming has been around since the caveman; we're just smart enough to record it!

Back to cormy's...they probably play more of a role on the bait fish. Everything from a shiner minnow to perch.

Things that a walleye eats. Yes they can dive deep and swim fast, but they will take the easier meal like everyone else.

There is more to blame than just one force. And walleyes didn't just vanish. It's a big puddle. Little by little the numbers dwindled.

Food for thought: Maybe no slot and all the attention put a hard slam on the population...unlikely, but I bet we had something to do with it too!

Good Luck!