Appreciate your fishery

I recently attended a results seminar for a 5 year DNR study on the flathead population in my nearest river, the Wolf here in Wisconsin.

Setlines and bank poles are still legal on the Wolf River.

The study was brought about because in 1997 a group of setline anglers went to the DNR complaining about the contunied decline in the size and numbers of both their flathead and channel cat catches.

The study was funded for 5 years, 2001-2006. Right off the bat, the comercial sale of flathead catfish from the Wolf river was outlawed and the bag limit was reduced to 2 per day with a 10 fish possession limit.

After 5 years of collecting date the DNR estimated that there were 20-24 flatheads per river mile.

20-24 x 90 miles = 1,800-2,160 total flatheads.

These numbers are well below the river’s potential and the DNR representative stated that a severe overharvest problem was evident.

Further numbers showed that 300 setline permits were purchased last year and each person was given a survey sheet to record his catch data. About 200 surveys were returned that inducated an average of 2 flatheads harvested per angler per year. A bell-curved show most of the kept fish were 15-20 pounds and very, very few were released.

300 setlines x 2 fish harvested = 600 fish removed from the river.

Now, these two statistics were presented at two different times during the talk and, taken one at a time, didn’t seem unbelievable. Their combined significance did not hit me until after the meeting.

I have a hard time beleiving that they can both be correct.

Is it possible that they havested over 25% of the flatheads last year?

I have sent an email to try and get a clarification on the specifics and will post again if I have made a mistake.

Anyway, such is life as a hook and line catfish angler on my home river.

Seems pretty excessive, in 4 years, the river would be pretty much void of flats ?

big g

Its most definately a chunk either way regardless of how accurate the overall population, or harvest numbers are.

Flatheads make lots of babies.. but it takes time to grow even 20# fish.

Hopefully they can come up with somethin to protect the fihery and let it rebound back to where it should be now that they are aware of the issues and damage caused to the fishery.

Hopefully youve misunderstood, however if not it seems to me they need to protect these fish, just as they would walleye or anything else, Im beginning to see that managers need to be assigned to rivers and lakes to survey these important issues.

20-24 flatheads per river mile seems very low – it can’t possibly include flatheads not yet sexually mature or this river wouldn’t have flatheads at all. I’d like to see how they came up with their estimates and just what they mean – interesting stuff regardless – did they publish? Do you know if there’s a way to access their full writeup?

Is there a dam on the Wolf or can fish migrate up from another river?

Yeah the 20-24 is “mature” fish. I’ve been looking online today and all I can find are news articles about the study, here it one quote:

“Based on data collected through 2004, Niebur said the best guess is that
there are 2,022 mature flatheads in the Wolf River, about 20 for each river
mile. The largest captured so far was 48 inches long and weighed 58 pounds.
The average weight is 16 pounds.”

I know they used hoop nets, electrofishing and angler cooperators. It says that from 2002-2004, 843 of the 1600 sampled flatheads were provided by setline anglers. That confirms the potential harvest these setlines can make. A handfull of cooperators caught 843 flatheads in 3 years!!

I know they sampled in 2005 and 2006 and got more fish each year than the year before due to refined techniques.

They showed an underwater video from 2006. Water temp 37 degress the dove into the wintering holes and counted the fish and put hundreds in keep bags by hand. Just grabbed them and put them in the bag. They were all tagged and recorded then the divers took them all back to the bottom and placed them back with the other flatheads.

No dams on the Wolf.

The Wolf is connected to the Fox which flows into Green Bay, but radio tagged flatheads in the study have proved that the Wolf River fish stay in the Wolf and the Fox River fish stay in the Fox. There was no overlap in their travelings.

Hey RB good post! Makes a guy think.

And also makes a person appreciate the Mighty Mississippi and it’s cat system more.

In fact, I think I’ve been under estimating the waters we have in our neck of the woods.

I’ve talked with a commercial netter that has taken out 1600 pounds of cats over two days out of our area. There was no breakdown of channels/flats and I would assume more would be channels…but I don’t know that. The commercial guys have been netting five times that I know of…and since I don’t track them…I again would assume more. They’ve been doing this for years and we still have an awesome fishery.

I’ve always wondered why the DNR didn’t watch for snagging closer as in my mind it would wipe out the entire fishery…but the truth is (for this river anyway) that the flathead population is not in danger.

I guess my point is…you are very right, we should, including I appreciate what we have more.

On to another subject. I was very fortunate to have lunch with a veteran DNR biologist a couple weeks ago. He’s been the fella in charge of the sturgeon studies on the St Croix River. I have the DNR’s Lake Sturgeon Assessment of te Lower St Croix River next to me. (2003-2006)

The project goal was to assess the overall health of the lks population in the St Croix…one of the factors in doing this was to develop a population estimate.

I can’t hammer out all the numbers here…but I’ll type out the higher of the two estimates.

Schnabel estimate:

unmarked Total Pop’n

Sample period Tagged Captured recaps Estimate

2003 34 34 0 n/a

2004 36 36 0 n/a

2005 65 68 3 1995

2006 153 160 7 2,758

Now when the guys on IDA that have fished the Croix read these numbers and get the TOTAL population estimate for the Lower St Croix River is less than 3000…I’m thinking that thread is going to turn into a bunch of

The DNR in fact knows that they have too small of a sampling to get a even close estimate.

The DNR will be asking us for our help this fall to help with their studies, but more on that later this year.

My point is, if I wouldn’t have fished the river, I would have said, wow that’s a low population. With a conversation wrapped around why the numbers are the way they are…it all makes sense, there needs to me more fish caught to get a more accurate number.

Here’s another tid bite of info. I was talking with a biologist out of the Lake City office as I heard they were netting sturgeon in the area of Pool 4. I asked how many they caught…I don’t remember the number they said, but it was less than 5…and they were smaller ones. I scratched my head and asked how they were netting them. Turns out they were using a net that is dragged by the boat which allows the larger, faster LKS to escape. But they did net “a large number” of short nosed sturgeon.

Now that I’m completly off topic, I might as well go the whole way.

Of the tags that MN/WI sold for the St Croix in the fall of 2006, four tags were filled.

Dtro made this observation over a year ago. The DNR shows that the St Croix Sturgeon weighs less than a sturgeon of the same length that was caught in a lake.

Out of all of this, I’ve learned a number of things…

1) I have a lot to learn

2) Take time to get to know the DNR biologists (they are people too), you might be surprised what a fella can learn from them.

3) We live right smack in the middle of some of the greatest fisheries in North America

4) I under appreiate what I have in my own back yard!

Here was my email to the DNR:
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Al, I was just thinking about some of the numbers you presented on Monday night. If I recall correctly, you stated there were 20-24 flatheads per river mile in the Wolf.

24 fish x 90 miles = 2160 total fish

I think you also stated that around 300 setlines were registered per year. With the average harvest being around 2 fish per year.

300 setlines x 2 fish = 600 fish

Is that correct?
Are they harvesting almost 30% of the total estimated population each year with most of them being 15-20 pounds?
—————————————————————————————

And here is the response:

Notice the difference in the scale on the Y axis of his charts. This fishery is being devestated.

———————————————————————————-
Yes, you are correct. In addition, our tag return information has somewhat corroborated our population estimates and harvest reports. The population appears to be under some very high harvest rates. Based on tag returns from our cooperators (volunteer angler reports) we estimate exploitation of our large (>24 inch) flatheads at about 25-35%. Now keep in mind my population estimate is being calculated for 24 inch and larger adult flatheads. We still don’t have a good handle on the juvenile size flatheads in terms of a P.E. and recruitment is still unknown. WE hope to clear that up with more data collection. I didn’t show some of the more intense analysis I have conducted but based on a yield model with current growth data it appears that the population has significant room for improvement in numbers and biomass. The two charts I pasted into this email show some of the modeling . The first chart is yield (or production in biomass) of flatheads at 30% exploitation rates and the next chart is an unfished situation. Take note of the difference in biomass with each scenario.

At any rate, we are working hard to try and resolve this issue with our catfish citizen advisory committee. I hope we will coming to the 2008 spring hearings with a package of potential regulation changes to resolve some of the over-exploitation concerns. What those will be still needs to be discussed.

Stay tuned and feel free to call or email if you have any other questions. Thanks for your interest.
——————————————————————

Current flathead biomass chart

Potential flathead biomass

It those numbers are even half right, (I have no reason to doubt them) it’s no wonder people were complaining about the fishery.

RB, has there been a “run away” population explosion from some other fish?

I guess it would be good to know the sampling size for each of the years…could you ask your contact for that info?

I don’t want to give the wrong impression that I thing the numbers are wrong….but my nature is to ask questions.

Bottom line is that it’s REALLY too bad that they have to wait until ’08 for hearings.

Quote:

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Schnabel estimate:
unmarked Total Pop’n
Sample period Tagged Captured recaps Estimate
2003 34 34 0 n/a
2004 36 36 0 n/a
2005 65 68 3 1995
2006 153 160 7 2,758

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Uh, yeah. That seems laughably low!!!

I didnt keep track of the actual number of sturgeon we put in the boat last year, but I can tell you I fished them more than 20 times and probably averaged 20 fish per trip overall. Some outings had many more fish than that. I kno of other boats around that caught even more with smaller baits(crawlers) that pulled really high numbers regularly becuse the smaller fish were a larger part of the catch.

Giving a rough estimate of 400 fish caught, it would really be hard to swallow 2700 fish in the lower part of the river.

I might be inclined to believe 10 times that amount.. closer to 30,000… or more. They’re arent many places on the river you wont catch at least 1 fish.

Brian, I know they sampled well over 3,000 “mature” flatheads during the 5 years.

I’ve asked if the study finding are available to the public, hopefully I can get a look at the numbers again.

I made my own chart using the same data points to better show the problem.

There’s only one word to describe that chart…OUCH!

To the LKS numbers…in the defense of the guys working on the survey…they could only fish in their “spare” working hours. Meaning, if they had their other work done, they could finish out their 8 hours by tagging.

Quote:

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I made my own chart using the same data points to better show the problem.

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Thanks for making that – it isn’t apparent right away that the two charts have such different scales – this is a much better visual.

A question I have every time I think about commercial harvest of flatheads or even personal consumptive uses of 15-20lb fish is, “where is the market?” Who’s eventually eating these fish and have they heard about methyl mercury? The Wolf is not as polluted as the Fox or the Mississippi (I think) but predators still accumulate whatever is there very quickly – these are not fish that people should be eating. And they are DEFINITELY not fish that people should be eating unaware of their source. Is there a market and are there guidelines or regulations pertaining to the quality (PCB and mercury content, specifically)??