Walleye Express
01-06-2004, 08:24 PM
[b] This is a fallow up response to a post Tom O addressed to me reguarding an article in the Woods and Waters news, concerning the abundance of both perch and walleyes observed in the trawl nets that our DNR dragged on the Saginaw Bay this September. I contacted Michigans head DNR biologist (a bud of mine) and asked him to send me the skinny on that trawl results, along with any of his personal obsevations if any. Also invited him to maybe be a Michigan DNR answer man the way the Ohio guy is, to answer our questions here on Walleye Central. Below is mine and his e-mail correspondence today.
Dave.
Long time no hear hey? Can I get the official September trawling results you guys did on the Bay? I just heard they had really exceptional results. Also wouldn't mind getting your spin on why you think the bigger walleyes haven't showed up in the river this fall. I have the feeling it has to do with temperature and forage, but would like your spin on it. I'd also like to talk to you about maybe being a go-to answer man for some of the questions the guys on Walleye Central always have about technical scientific questions concerning walleyes on the Bay and the environment. Dan
Hey Dan:
Good to hear from you.
I'm not sure exactly what you have heard, but yes something
extraordinary has happened on Saginaw Bay. We went out to do our annual survey work like we do each September and detected record numbers of young-of-the-year (YOY) walleye and yellow perch. Right now I'm in Sault Ste. Marie Ontario attending a workshop so I don't have all the exact numbers in front of me but the catch rate of the YOY walleye was something like 31 times greater than the average and nearly five times greater than back in 1998 (which was the previous record)! I can't recall the yellow perch YOY numbers but their catch rate was equally substantial.
Right off the bat we thought of the record plant of walleye fingerlings made this year, but there were too many walleyes to be explained by that alone. Our analysis of the OTC mark on the hatchery fish is continuing, but its looking like it will confirm that the vast majority (like maybe 85%) of the year class is from natural reproduction (not stocking). Lake Erie has similarly had a record year class of walleye production this year too so it looks like ideal climatic conditions are to be credited. I also suspect that the low abundance of adult alewives in 2003 favored good survival of wild walleye fry (remember the alewives prey upon and compete with the newly hatched walleye).
Needless to say this is an extraordinary event in the history of Saginaw Bay. However, there are some things to bear in mind. First; they have to survive the winter before we can really count them as "recruited" to the population. That first winter often claims a lot of new fish. Fortunately, this winter is shaping up to be fairly mild and even if we lost most of these fish, it'll still be a very large year class. Second; this is such a new sort of thing for Saginaw Bay, no one feels comfortable making predictions yet as to what this will mean exactly for fishing. For example, even though the catch rate in our trawling is something like 31 times greater than normal, it wouldn't be accurate to predict that fishing is going to be 31 times better. Still, almost anyway you look at it, this good news, especially for walleye, but still exactly how it will impact fishing is not clear right now. One potential problem (especially for the perch) is that there may be so many, that their growth rate will slow way down. Remember back in the late 1980s and early 1990s how the perch were nearly stunted in Saginaw Bay. We don't want to go back to that.
We will know a lot more after next year. A year from now, we'll be in a better position to understand exactly what the implications are. It
raises a lot of questions and we have some time to think things through before these fish enter the fishery. In the mean time, anglers (next summer) will likely start catching a lot more young (sublegal) walleye. They probably won't be 15 inches until 2005. We, in the DNR will be meeting about Saginaw Bay in February to review all the data and to discuss these turn of events. We'll be better able to offer up some explanations then. This record level of production is forcing us to reexamine some of our assumptions and beliefs about the bay. There are implications for our new recovery plan. Mostly, this will be a good jump start to reach our goals. Does this mean the walleye population is recovered? No. The conditions that led up to this are likely very unique and we may not see anything like this again for a long time. Still, the presence of a very strong year class like this can help the set the stage for better years in the future. Let's hope.
I'll get back to you in February with hopefully more specific
information then.
As for the big walleye not being in the river this fall; I'm not certain except it's always been my belief that they entered the river in the winter for two reasons. One is to pursue forage fish that inhabit the river in the winter and two is to seek a thermal refuge (i.e. to escape the colder bay water temps). If they aren't there this year, then it suggests that maybe the forage fish aren't in the river in their usual abundance &/or the river isn't offering the usual thermal advantages that it sometimes does. Consider that adult alewives are down (fewer) in the bay this year; maybe they aren't using the river like they do in some years. Also consider that this is shaping up to be a relatively mild winter. Maybe the river isn't much warmer than the bay itself. These are sort of only guesses on my part, but they may offer clues as to what's going on.
As to your offer/suggestion that I serve as some sort of technical
expert for the discussions on the Walleye Central Message board; first
let me say that I am flattered that you would think of me as there are
lots of other "experts" out there as well. I do read over the
discussions taking place there from time to time and am often tempted to weigh into the discussions. For now, maybe the best option is for you to bring a question to me from time to time as opposed to inviting folks to contact me directly. I guess that would be my preference as I am reluctant to sign on to anything more not fully knowing what it might amount to in terms of e-mail traffic. Thanks for asking first.
Hope this helps Dan. Keep in touch.
-Dave
Dave.
Long time no hear hey? Can I get the official September trawling results you guys did on the Bay? I just heard they had really exceptional results. Also wouldn't mind getting your spin on why you think the bigger walleyes haven't showed up in the river this fall. I have the feeling it has to do with temperature and forage, but would like your spin on it. I'd also like to talk to you about maybe being a go-to answer man for some of the questions the guys on Walleye Central always have about technical scientific questions concerning walleyes on the Bay and the environment. Dan
Hey Dan:
Good to hear from you.
I'm not sure exactly what you have heard, but yes something
extraordinary has happened on Saginaw Bay. We went out to do our annual survey work like we do each September and detected record numbers of young-of-the-year (YOY) walleye and yellow perch. Right now I'm in Sault Ste. Marie Ontario attending a workshop so I don't have all the exact numbers in front of me but the catch rate of the YOY walleye was something like 31 times greater than the average and nearly five times greater than back in 1998 (which was the previous record)! I can't recall the yellow perch YOY numbers but their catch rate was equally substantial.
Right off the bat we thought of the record plant of walleye fingerlings made this year, but there were too many walleyes to be explained by that alone. Our analysis of the OTC mark on the hatchery fish is continuing, but its looking like it will confirm that the vast majority (like maybe 85%) of the year class is from natural reproduction (not stocking). Lake Erie has similarly had a record year class of walleye production this year too so it looks like ideal climatic conditions are to be credited. I also suspect that the low abundance of adult alewives in 2003 favored good survival of wild walleye fry (remember the alewives prey upon and compete with the newly hatched walleye).
Needless to say this is an extraordinary event in the history of Saginaw Bay. However, there are some things to bear in mind. First; they have to survive the winter before we can really count them as "recruited" to the population. That first winter often claims a lot of new fish. Fortunately, this winter is shaping up to be fairly mild and even if we lost most of these fish, it'll still be a very large year class. Second; this is such a new sort of thing for Saginaw Bay, no one feels comfortable making predictions yet as to what this will mean exactly for fishing. For example, even though the catch rate in our trawling is something like 31 times greater than normal, it wouldn't be accurate to predict that fishing is going to be 31 times better. Still, almost anyway you look at it, this good news, especially for walleye, but still exactly how it will impact fishing is not clear right now. One potential problem (especially for the perch) is that there may be so many, that their growth rate will slow way down. Remember back in the late 1980s and early 1990s how the perch were nearly stunted in Saginaw Bay. We don't want to go back to that.
We will know a lot more after next year. A year from now, we'll be in a better position to understand exactly what the implications are. It
raises a lot of questions and we have some time to think things through before these fish enter the fishery. In the mean time, anglers (next summer) will likely start catching a lot more young (sublegal) walleye. They probably won't be 15 inches until 2005. We, in the DNR will be meeting about Saginaw Bay in February to review all the data and to discuss these turn of events. We'll be better able to offer up some explanations then. This record level of production is forcing us to reexamine some of our assumptions and beliefs about the bay. There are implications for our new recovery plan. Mostly, this will be a good jump start to reach our goals. Does this mean the walleye population is recovered? No. The conditions that led up to this are likely very unique and we may not see anything like this again for a long time. Still, the presence of a very strong year class like this can help the set the stage for better years in the future. Let's hope.
I'll get back to you in February with hopefully more specific
information then.
As for the big walleye not being in the river this fall; I'm not certain except it's always been my belief that they entered the river in the winter for two reasons. One is to pursue forage fish that inhabit the river in the winter and two is to seek a thermal refuge (i.e. to escape the colder bay water temps). If they aren't there this year, then it suggests that maybe the forage fish aren't in the river in their usual abundance &/or the river isn't offering the usual thermal advantages that it sometimes does. Consider that adult alewives are down (fewer) in the bay this year; maybe they aren't using the river like they do in some years. Also consider that this is shaping up to be a relatively mild winter. Maybe the river isn't much warmer than the bay itself. These are sort of only guesses on my part, but they may offer clues as to what's going on.
As to your offer/suggestion that I serve as some sort of technical
expert for the discussions on the Walleye Central Message board; first
let me say that I am flattered that you would think of me as there are
lots of other "experts" out there as well. I do read over the
discussions taking place there from time to time and am often tempted to weigh into the discussions. For now, maybe the best option is for you to bring a question to me from time to time as opposed to inviting folks to contact me directly. I guess that would be my preference as I am reluctant to sign on to anything more not fully knowing what it might amount to in terms of e-mail traffic. Thanks for asking first.
Hope this helps Dan. Keep in touch.
-Dave