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Results of landmark LMB study released

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The results of 20-year largemouth bass study done out of the Univ. of Illinois has just been released. You can read about them here:

http://www.sciencedaily.com/releases/2009/04/090414153532.htm

Although there no real surprises, there are few notable findings and recommendations:

1. Vulnerability to being caught appears to be a genetic trait. This means that a body of water can become harder to fish over time not because the fish are getting smarter but because, unless catch and release is practiced, the LMB who are genetically predisposed to getting caught get selected out. In other words, catchability might be inherited and not learned.

2. Catch and release is somewhat irrelevant during spawning season. Researchers determined that male bass removed from a nest for more than few minutes likely destroys the nest as other fish quickly move in to feast on the eggs.

3. The researchers expressed concern over the explosion of bass tournaments held during the spawning season, when large numbers of males are removed from nests for long periods. "There should be no harvesting bass during the reproductive period," one of the researchers says. "That makes sense for all wildlife populations. You don't remove the adults during reproduction." He recommends creating spawning sanctuaries for at least a portion of most lakes, making fishing there off limits while the nests are active. That, he says, would "help protect the long-term future of the resource without completely restricting fishing."

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Thanks for posting.  This is an interesting article.

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Quite opposite of Texas Parks & Wildlife research ;)

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3. The researchers expressed concern over the explosion of bass tournaments held during the spawning season, when large numbers of males are removed from nests for long periods. "There should be no harvesting bass during the reproductive period," one of the researchers says. "That makes sense for all wildlife populations. You don't remove the adults during reproduction." He recommends creating spawning sanctuaries for at least a portion of most lakes, making fishing there off limits while the nests are active. That, he says, would "help protect the long-term future of the resource without completely restricting fishing."

Personally, I don't intentionally fish for bedding bass. However, I have

turned around on the issue itself. Many researchers have written that

bed fishing has no impact on bass populations and in fact may be

beneficial for some bodies of water (overpopulated).

Lake Fork is a case in point: I have never been to another lake that

was fished so hard, especially during the spawn. Yet, the lake continues

to produce numbers and size!

8-)

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I would also question the merit of the 3rd point.  Sure the eggs/fry are eaten, but bass are prolific reproducers so the effects of destroying a few nests is neglible for the population overall.  

Another way to look at this is that the bluegill or other bass egg/fry predators are going to get their share of the hatch.  Do they get the easy pickings because an angler pulled the male off the bed or do they have to work a bit harder to catch the errent fry?  Overall the effect likely nets to near zero.

The nesting effects point kind of sounds like the scientists opinion rather than part of the research.  His research doesn't appear to have taken into account the actual effects on the overall population of bass when anglers fish during the spawn, instead he is taking a narrow point (effects on a single nest) and extrapolating that across the entire lake/population when his study did not cover that.  Seems like a leap to me.

The heriditary aspects of "catchability" is definately interesting though.

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No research ever established what the number or percentage of successful spawns for that spawning season to be successful.  What I am saying, is most are not going to make it to adult hood anyway.  How many successful spawns need to occur to be beneficial to the population, both in numbers and in size.

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I certainly wouldn't call it a "landmark study". Interesting, yes. The whole spawn issue is widely disagreed even amongst the various state agency personnel. Our own state (Indiana), and neighbor to the state where this research was done, just recently published a paper arguing against a closed season here on the basis of previous studies and biologies.

Plus there is the question of if bass catchability were truly inherited to a high degree, after nearly 40 years of tournies and increasing pressure, how is it we can still even catch these green fish to the degree that we do?

Their answer to that question was less than satisfactory in my mind.

-T9

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As a nonscientist and an amateur angler, I'm going to stay mostly out of this one, but it's important to keep the facts of this study straight, at least as this nonspecialist understands them.

I certainly wouldn't call it a "landmark study".

I would. Or at least this: a 20-year controlled study would be widely viewed as an unusually comprehensive exercise in data gathering, I think.

The whole spawn issue is widely disagreed even amongst the various state agency personnel.

Not sure what you mean by personnel. Regulators? Managers? Scientists? I'm most interested in the latter and don't know enough about LMB research to characterize how this one study fits in. I have a feeling that these researchers, like most scientists, would shy away from a one-size-fits-all fisheries management approach. The conditions on the ground at each water body need to be taken into consideration, of course, but certainly one of the bedrocks of wildlife management policy since at least the 1930sat least as understood from this layman's erratic reading through the yearshas been to minimize the harvesting of breeding adults.

Our own state (Indiana), and neighbor to the state where this research was done, just recently published a paper arguing against a closed season here on the basis of previous studies and biologies.

I think these researchers are calling not so much for a universal closed spawning season as for the setting aside of spring spawning sanctuaries where appropriate, an approach that has been successful with a lot of other species.

In general, the question "If the resource is declining, why are people catching so many bass?" is a bit of a red herring (pun intended). The only way you can answer the question is by looking at a body of water where the catch during spawning was at least partially restricted over the same time period. I remember a lot of years ago driving around a remote part of Cape Breton with a local writer and marveling at all the wildlife we were seeing. His response was you should have seen it 150 years ago. And he's right: the definition of what constitutes plentiful gets adjusted downward with each generation. If you read some of the 19th century nature writers, they describe overflights of passenger pigeons that would literally block out the sunlight for hours at a time. Now they're extinct. The point is not that the same thing is happening to LMBI'm catching them just fine, thank youbut that it's useful sometimes to question our assumptions.

If any of you fisheries scientists out there can add links to summaries or full text of other reputable LMB studies into this discussion, that could be really helpful in judging this one. Meanwhile, I'm going to try to drop an e-mail to these researchers and invite them to join the discussion and clarify their position.

Norman

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Interesting article.

I think the statement from the article:

if bass are angled and held off of their nests for more than a few minutes, when they are returned to the lake, it's too late; other fish have found the nest and are quickly eating the babies.

This is true in some waters (with high sunfish density) but not so for waters without. I see both situations existing in adjacent ponds.

I've always had this concern about catching males off beds. While some studies have shown that it only takes a few successful beds on a good hatch year to create a good year class, I have to argue that this argument misses the food value good hatch years can bring to the mature bass in that water body. YOY are great food for mature bass in a lot of ponds I fish. I'd like to see more YOY bass not less. We can cull 'em (for growth of remaining bass) after they grow too large to be considered bass food.

Wherever I've fish, males are vulnerable to anglers and on popular waters many are caught repeatedly and to a state of exhaustion.

Another quote from the article:

"Most of the selection is occurring on the LV fish that is, for the most part, the process is making that line of fish less vulnerable to angling. We actually saw only a small increase in angling vulnerability in the HV line," Philipp said.

I guess I need to see the original article.

Team9nine wrote:

Plus there is the question of if bass catchability were truly inherited to a high degree, after nearly 40 years of tournies and increasing pressure, how is it we can still even catch these green fish to the degree that we do?

I can answer that one. Bass are way more vulnerable to angling under low visibility conditions, and much less so under high vis conditions. We mostly get our licks in under deep overcast, and our butts kicked when it's sunny. We can adapt by fishing deeper, or into cover, but it just isn't the same as a good dark day. Heck, I'll even settle for a light wind ruffling the water sometimes.

Best case scenario: Give me a pond that's NEVER been fished, either sunny or cloudy.

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Well, back to Lake Fork:

If some percentage of the bass population "learn" anything

individually or over generations, then every retarded fish in

Texas would have to call Lake Fork home.

::)

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Well, back to Lake Fork:

If some percentage of the bass population "learn" anything

individually or over generations, then every retarded fish in

Texas would have to call Lake Fork home.

::)

I don't know, Kent. They seemed pretty smart when we down there a couple of years ago on the BR trip! ;)

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The whole genetic manipulation through fishing would only work if ALL bass caught were harvested.  Otherwise, its like saying that if I lost my arm, then all my children will be missing an arm as well.

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Correct me if I'm wrong but this study was preformed on only one lake right?

How could that represent every lake in the country?

There is one thing that I have learned about Scientists. The money for studies like this come from the Government. Therefore they can be manipulated by polititions and special interest groups. The response in #3 makes me question the motive of the person or people who conducted the study. From that statement they are suggesting that we put a stop to all forms of hunting animals as well as fishing during the spawn. I wonder what special interest groups they might be affiliated with.

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The whole genetic manipulation through fishing would only work if ALL bass caught were harvested.

Unless angling affects nest success. Then angling would affect success of those males most vulnerable to angling.

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From that statement they are suggesting that we put a stop to all forms of hunting animals as well as fishing during the spawn. I wonder what special interest groups they might be affiliated with.

That thought crossed my mind too. But, after re-reading it I doubt there's anything insidious there.

In this case, "protecting the resource" is about protecting catchable fish, not the species. The author's are well aware that bass as a species are not threatened or endangered in any way.

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For discussions sake, a few more comments. I have at home and have read the entire research paper, not just the Science Daily article/synopsis of the study, so I've seen and am familiar with all the little details involved with the study.

1 - I still stand by the statement of not a landmark study as based on the defintion of landmark: "an event that marks a turning point". I don't see where the "turning point" is in our understanding of bass because of this study. Long, disciplined, well-designed, neat, etc. - Yes.

As for who I was referencing it is state DNR fishery biologists. 35 of our 50 states have absolutely no type of closed season or restriction in place for fishing bass off the beds, largely because the belief by these professionals is that especially in southern and western waters, at the populatoin level there is little to support this type restriction. The Indiana study just released can be found here:

http://www.in.gov/dnr/fishwild/files/Bass_on_Beds_Final.pdf

The last comment was a bit of a setup. They propose the question in their summary, and I copy it verbatim for you here with their explanation:

"In light of this new evidence, one might ask why there are not more examples of fish populations in the wild showing such drastic responses to angling-induced selection or why there have not been widespread decreases in largemouth bass catch rates if the vulnerability to angling has in fact decreased. We speculate that the failure to observe such changes in angler catch rates is due to the tremendous increases in angling technology (e.g., the advent of better terminal equipment, the development of fish locating devices, and the improvement in boat design and handling characteristics)."

I ain't buying that explanation...

On the refuges, that is a mixed bag. I've seen one study on largemouth that showed larger adult populations in refuges, but there were actually more non-mature bass in non-refuge areas. Modeling studies with bluegill suggest that closed areas don't protect large males sufficiently to maintain their population. There are some studies in saltwater that suggest benefits to refugia if the closed area is large enough and permanent. So we really don't know for certain in that area, and I'm guessing most fishery biologists wouldn't want to err on the side of caution by enacting regulations on waters that would restrict that access of anglers due to the unpopular nature of such a decision.

-T9

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Hey Gene; The same thing can be said about the other side of the coin. The tackle and tournament industries also will manipulate and hide facts to protect their incomes

 There were some photos here, that a member/sponsor had of a Large Bass Kill, well documented at FALCON LAKE. This kill was due to BASS not allowing for the rather large 5 bass weights in the live wells.

 I found those photos on the Internet then 4 days later they were gone forever, i bet both the tackle and tournament interests in Texas had a lot to do with that.

You can not completely discount a 10 year, scholastic/scientific research project, and i agree some involved will try to manipulate stuff to their point of view

 I have been fishing and reading about fishing since I was young and both the tackle industry and the Tournament Trails, have on more than one occasion suppressed and distorted information that could ultimately case a loss of monies in their pockets

Nice Link Norman 8-)

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The whole genetic manipulation through fishing would only work if ALL bass caught were harvested.

Unless angling affects nest success. Then angling would affect success of those males most vulnerable to angling.

I think that is a HUGE stretch.  By that logic you can flip this around to be a negative, the fish that are most vulnerable to angling would not be protecting their nests very well, and therefore the young would never make it.  I think you're oversimplifying the correlation between biting a bait/protecting the nest and the behavior of adult progeny from those nests.

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The results of 20-year largemouth bass study done out of the Univ. of Illinois has just been released. You can read about them here:

http://www.sciencedaily.com/releases/2009/04/090414153532.htm

Although there no real surprises, there are few notable findings and recommendations:

1. Vulnerability to being caught appears to be a genetic trait. This means that a body of water can become harder to fish over time not because the fish are getting smarter but because, unless catch and release is practiced, the LMB who are genetically predisposed to getting caught get selected out. In other words, catchability might be inherited and not learned.

2. Catch and release is somewhat irrelevant during spawning season. Researchers determined that male bass removed from a nest for more than few minutes likely destroys the nest as other fish quickly move in to feast on the eggs.

3. The researchers expressed concern over the explosion of bass tournaments held during the spawning season, when large numbers of males are removed from nests for long periods. "There should be no harvesting bass during the reproductive period," one of the researchers says. "That makes sense for all wildlife populations. You don't remove the adults during reproduction." He recommends creating spawning sanctuaries for at least a portion of most lakes, making fishing there off limits while the nests are active. That, he says, would "help protect the long-term future of the resource without completely restricting fishing."

for number two, that is a big reason for why we have seasons up here in canada for those of you who ask me why there is such a thing.

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Ridge Lake Biological Station Charleston, IL

Ridge Lake is well-stocked with bluegill, largemouth bass and channel catfish.

Ridge Lake is open to the public for fishing each year from Memorial Day weekend through Labor Day weekend.

http://www.inhs.uiuc.edu/cae/kaskaskia/BioStations/stations/ridgelake.html

http://www.inhs.uiuc.edu/cae/kaskaskia/BioStations/other/research.html

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interesting thanks for posting

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In all do respect for the article, I may have my off year that

I don't do well but for the past  sixteen years I have been out fishing for bass not much has changed.

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The whole genetic manipulation through fishing would only work if ALL bass caught were harvested.

Unless angling affects nest success. Then angling would affect success of those males most vulnerable to angling.

I think that is a HUGE stretch. By that logic you can flip this around to be a negative, the fish that are most vulnerable to angling would not be protecting their nests very well, and therefore the young would never make it. I think you're oversimplifying the correlation between biting a bait/protecting the nest and the behavior of adult progeny from those nests.

If angling impacts nest success by catching the male (as the research in this case stated occurs) then one would expect a difference in relative success between HV and LV male bass. If LV bass fail to raise broods and HV succeed, there is selection at work, at the hands of anglers.

I do not know whether this is so, I have no data and no opinion, just trying to clarify what the author's appear to be getting at. This IS a way that selection by angling for HV bass could occur in C&R fisheries. The other question there, and maybe what you are questioning, is whether HV status extends into nest defense behavior. Good question.

The authors also address mortality in tournaments -which can reach 30% in some summer Ts. This is a more direct and obvious selective force.

"In light of this new evidence, one might ask why there are not more examples of fish populations in the wild showing such drastic responses to angling-induced selection or why there have not been widespread decreases in largemouth bass catch rates if the vulnerability to angling has in fact decreased. We speculate that the failure to observe such changes in angler catch rates is due to the tremendous increases in angling technology (e.g., the advent of better terminal equipment, the development of fish locating devices, and the improvement in boat design and handling characteristics)."

Not sure about this one. My guess is (taking the easy road here lol) that there is much more to the question than genetics. Learning in individual fish, variable competition due to cohort size, visibility, as well as angler know how and technology (think of deep water fishing before and after Buck Perry) all enter in.

I'd like to know something about the behavior of HV bass to angling. Are they smarter, live in odd locations, or just plain spooky? Probably all three enter in.

Trout managers in the UK think C&R is suicidal (to the fishing quality). They kill every fish, and intensively manage their fisheries for production and growth. They don't want their brown trout any smarter than they already are.

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As usual, good points Paul.

The other question there, and maybe what you are questioning, is whether HV status extends into nest defense behavior. Good question.
Yes, Paul, I was referring to that correlation. It appears to be an assumption on the authors' part. A huge one, at that.

The authors also address mortality in tournaments -which can reach 30% in some summer Ts. This is a more direct and obvious selective force.
I would say be careful with that figure. It was that high in one tournament recently, but that is far from the norm. Or is it? I'm not sure we really know. I do know that I can only recall two dead fish (small smallies) in a tournament I participated, and these two came from the same livewell, on the same day. I'm going to assume something went wrong here, mechanically or handling wise. I seem to recall 10% being a maximum mortality target.

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I agree that the first correlation with the males is an assumption that should have been backed by more hard facts.unless we do not have the whole list of addendum's or research citations.

Mortality due to tournaments: This is the one I have never seen a study on DELAYED MORTALITY that was scientifically done. How many caught fish die within 48 hours of being released? Would they all be floaters? What is the result for lets say 5 years of several tournaments, by very accomplished fishermen on a given body of water?

This is the question I wish would be answered thoroughly! Greenwood Lake NY/NJ, was listed as one of the best bass lakes in the North East by BASS in the mid 70's , later the tour showed up and then many tournaments were held on that lake, and the numbers of LMB being caught fell and that lake has never been the same for LMB since, I would like to know if it was this fishing pressure or other factors that coincided with this. Many friends from different bodies of water , up here have similar tales, but there is no proof

The evidence for a single event in Texas, on Falcon lake led to denials and suppression, and I believe this was a single mistake but I also would love to see a study of post release mortality that actually means something

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