I bet we could all agree that over-harvest, whether by nets or anglers and regardless of time of year, is a bad thing.
I really am curious about the egg thing. I’ve always had a hard time believing that older fish aren’t good spawners but I definitely don’t know with certainty either way.
I bet we could all agree that over-harvest, whether by nets or anglers and regardless of time of year, is a bad thing.
I really am curious about the egg thing. I’ve always had a hard time believing that older fish aren’t good spawners but I definitely don’t know with certainty either way.
Hear, hear John. If we simplify things we all have some common ground for sure.
I’m with you. I’m sometimes amazed at the research published by the DNR (walleye telemetry study of p2 is a great example!) and other times left scratching my head at the total lack of scientific info available on certain topics like this one. Sometimes I wonder if the info is out there but not easily accessible. Or maybe they simply haven’t figured out how to conduct a reliable study on this yet.
Here’s an older thread that covers this topic, and others. At that time I did a bunch of digging and reached out to a number of people working for the DNR in MN and IA as well as some contacts involved with the oversight of fish hatcheries and there’s no evidence to support the idea that “big fish don’t spawn successfully.”
https://www.in-depthoutdoors.com/community/forums/topic/walleye_185321/
In other conversations with people working at hatcheries I’ve been told that big “brood” stock are not necessarily removed from the hatchery and released into the wild because they stop spawning successfully. It is often done because the largest fish eat too darn much and cost too much to maintain versus a number of smaller fish.
Regarding the health of off spring produced by larger walleye I’ve read some very interesting research regarding “fecundity” of eggs produced by larger walleye versus smaller fish. From memory, larger walleye produced larger eggs which resulted in larger fry which directly translates into a higher survival rate. I don’t have that research handy but will attempt to locate it and share it here.
IF people take anything away from the info I just linked I want it to be that people can call their local Fisheries Office and talk to really smart, passionate people that devoted their lives to protecting our resources. Ask them questions. They’ll answer.
The Mille Lacs net issue is not that they are taking egg layers, they are taking mostly males who fertilize the eggs… and even that is not the real issue. It’s that they are so easy to net during the spawn as they are predictable where they will congregate. The thought is, if the netting had to take place “after” the spawn… there would be less netting as it would require more effort.
The Mille Lacs net issue is not that they are taking egg layers, they are taking mostly males who fertilize the eggs… and even that is not the real issue. It’s that they are so easy to net during the spawn as they are predictable where they will congregate. The thought is, if the netting had to take place “after” the spawn… there would be less netting as it would require more effort.
Thanks G. Now that you mentioned it, I’ve heard that before. Makes sense.
Not trying to take the post of subject.
I personally don’t keep the big girls , it’s your right to if you want a keep the big fish. In ND on Devils the Fish and Game recommends you keep some of the big northerns. A lot of the smaller lakes are put and take fisheries with little to no reproduction, up to the individual.
Hey Guys,
Sorry I didn’t respond sooner. I just noticed the notification that zooks had asked for some information, and I have to get going to a meeting here soon, but I will try to mention a few quick points on the general topic. As BK mentioned I thought that I had posted something on here before about walleye egg production and walleye size, but couldn’t find it with a quick search. If someone else does please link it back here.
1) As a disclaimer I have never worked in a fish hatchery, but based on conversations with those who do and various articles I have read over the years the general gist is that as female walleyes get older/larger the percentage of eggs that are viable generally drops (the rate and magnitude of this drop likely varies for many reasons), BUT the greatly increased total number of eggs produced by large females as well as the proven growth genetics represented by those fish make them valuable contributors to the population.
2) Location matters — The article link at the top of the presentation was primarily using sources from Saskatchewan and Ontario. Walleye growth and longevity vary greatly based on the latitude (how far north you are) in their range. Walleye in Pool 4 grow much faster, mature at a younger age, and die sooner than walleye in more northern regions. I have attached a PDF document I posted several years ago showing the difference in growth rate measured by the MN DNR Large Lake program between Pool 4 and Rainy Lake walleye. This means that releasing a large fish in Pool 4 may allow it the possibility of spawning a few more times, where releasing a large fish in a more northerly lake might provide another decade of viable spawns.
3) Species matters — Fish species use different tactics to reproduce. Some of these involving behaviors like defense of a nest (ie Bluegill and bass) can be highly size dependent. Removal of large nest guarding individuals can lead to individuals maturing at younger ages (smaller size). When fish mature they tend to dramatically slow their body growth because they are putting more energy into reproductive structures and behaviors. This may mean a lower maximum size in a body of water (think Bluegill stunting). Based on this principal removal of large Bluegill is likely to have a higher impact on the size structure of a population than removing large Walleye.
Hopefully this answers a few of the questions folks have. I am sure it also will raise more. Feel free to contact me if there are specifics you are interested in.
Nick
Pepin-Walleye-Growth.pdf
Bravo. A topic I can get behind.
I was talking with a fish biologist who was visiting our fish camp on Lake Nipigon Ontario. He proceeded to explain that Northern Pike at 20 pounds out of Nipigon waters are generally aged at 40 years. Stop and think about that next time you want to keep your trophy northern from cold Canadian shield lakes
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