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Location: The desert | jlong - 1/2/2013 5:27 PM
jonnysled - 1/2/2013 5:55 PM i'm going back in the basement ... Good... now maybe some good discussion will occur on this thread. 
Care to wager on that? |
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Location: Warroad, Mn | I've always wondered why some great engineer didn't create a live well big and deep enough so it would hold most fish we catch. Then have a little line on it that says to fill to here wth water. Probably not too important as long at it covers the fish. Then when you put a fish in it there was a little float that went up and down like a gas guage. This would active a chip (computer stuff) that would send a message to a dial on your dash that says this fish weights X number of pounds. No doubt lots of problems with boat and fish movement, but I'll bet someone would sell lots of them! Probably not real accurate, but with refinement it maybe better than you would think, and lots of fun to argue about in the mean time. Doug Johnson
Edited by dougj 1/2/2013 7:42 PM
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Location: Elk River, Minnesota | Hi all,
Been following this with some chuckles here and there on how to get accurate measures and one thing stands in the way of both girth and volume displacement.... Girth changes on some fish as you measure at different parts of the body and as has been stated with using density as a means, it has error in it as well. If we assume uniform density in muskies, that assumes too much (fish in the belly being one of them), how much fat does a fish have, egg mass, etc....way too open for debate.
In my mind there is no better calculation than weight. Now...how to get it done? Use your net...
First, know the weight of your net (wet weight). Then, weigh the fish in the net by putting your scale on hoop of the net right by handle...or if you can lift it high enough, a bolt at the end of the handle. Get the weight, then subtract the weight of the net.
Another option, get an old muskie cradle, attach uniform lengths of rope to each handle end, then do the same calculation. Either way, you will get your weight measurement... The only issue is how accurate is your scale...
If it is for a record, it'll get you close, but it would still probably require a fish to be harvested.
Steve
Edited by VMS 1/2/2013 7:12 PM
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Posts: 549
Location: deephaven mn | does weight matter? the same fish say a 58" could vary in weight all season long. if you could catch it prespawn (possible in some states) it would most likely weigh the most, or november after a whitefish feeding binge. if you catch the fish in august
it may weigh 10 pounds less. my point is, it's the same fish, a giant! still a fish of a lifetime! so is it a greater success just because it was caught in the late fall compared to mid summer? |
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Location: minocqua, wi. | dougj - 1/2/2013 6:41 PM
I've always wondered why some great engineer didn't create a live well big and deep enough so it would hold most fish we catch. Then have a little line on it that says to fill to here wth water. Probably not too important as long at it covers the fish. Then when you put a fish in it there was a little float that went up and down like a gas guage. This would active a chip (computer stuff) that would send a message to a dial on your dash that says this fish weights X number of pounds. No doubt lots of problems with boat and fish movement, but I'll bet someone would sell lots of them! Probably not real accurate, but with refinement it maybe better than you would think, and lots of fun to argue about in the mean time. Doug Johnson
jlong doesn't mind density discussions depending on where it comes from doug |
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Posts: 906
Location: Warroad, Mn | The density of water is a function of temperature. If this is true for fish I don't know, but could be as they are cold blooded? Still I'll bet that a livewell scale is something that could be done. Still sounds like something a computer could figure out. JLong should be working on this! Doug Johnson |
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Posts: 62
| knock-knock-knock ..Penny... knock-knock-knock ..Penny... knock-knock-knock ..Penny ...
now that was a worthwhile thread !! thanks for the laughs Sled, IaJ, Cowboy and Lambeau, that was priceless problem solving !!
Keep it up, I will never buy cable tv just for the only show I like to watch !
( B.B. Theory) |
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| Okay Leonard...
I think what Jason was getting at was that if we are using weight as a barometer for calculating record fish, how do we establish a system/procedure for measuring that weight, and more importantly verifying and documenting that weight, that does not require killing the fish.
Throwing the "who cares?" arguments aside for a moment...
It seems a bit silly to carry a certified and calibrated scale. The simplest way is weigh yourself, pick up the fish, and weigh yourself again. Any digital bathroom scale can do that.
But what is to stop someone from stuffing downrigger balls in their coat pocket to add a few pounds? |
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Location: minocqua, wi. | as long as the down-rigger balls stay in your pockets you're good ...
didn't anyone watch bill nye??
l |
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Location: Eastern Ontario | Apparently Mike Lazarus carries a scale in his boat that has been certified by the IGFA. He recently weighed a 58 pounder for Ed Barbosa. Perhaps Larry Ramsell could explain how this works
Edited by horsehunter 1/3/2013 8:07 AM
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Posts: 1937
Location: Black Creek, WI | Just like people scoff at how many 49.5" muskies have been "stretched" to be reported as 50 inchers..... how often are girth measurements inflated? Perhaps some of the inflated numbers are not intentional due to lack of knowledge for how to properly take a girth measurement?
So... how many 52 inchers get inflated girths to reach the 40 pound mark?
52 x 23 = 34.4 lbs.
52 x 24 = 37.4 lbs.
52 x 25 = 40.6 lbs.
And... let's use Minnesota as an example. The State Record is no doubt a realistic goal these days based on the length of some of the fish getting released. Is 2 inches a feasible "mistake" when measuring girth? If you catch a 56 incher, I'm sure you will be confident in the length measurement. When you then decide to measure the girth, how confident will you be?
56 x 24 = 40.3 lbs
56 x 26 = 47.3 lbs
56 x 28 = 54.9 lbs and the new MN State Record.
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Location: The Yahara Chain | Where's Ramsell? Live girth vs dead girth is an issue.
Maybe sombody can start a new record keeping organization for volume. We could have modern and historical volume.
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Posts: 13688
Location: minocqua, wi. | what does a single pt. girth measurement do for accuracy??
completely inaccurate representation in a mass calculation even if it were taken correctly ...
assuming the discussion is about an alternative to certified weight (for you jerome)
Edited by jonnysled 1/3/2013 11:48 AM
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Posts: 1937
Location: Black Creek, WI | I agree, Bytor. Where are those willing to have a serious discussion? Lots of jokers commented... but seriously... I want to learn more about the girth measurement and how to use it. L x G x G / 800 is a volume equation, right? I'm assuming the 800 is a constant derived from all the conversion factors involved? Has anyone done the math themselves and are willing to explain all the assumptions made? Secondly, any error in the girth measurement is multiplied exponentially... in comparison to an error in the length. If length can vary by up to an inch pending whether you measure with an open tail or pinched tail... how much can the girth measurment vary? How tight should the seamstress tape be pulled? How do you ensure it is "square"? Do you take it while the fish is in the water, on a bump board, or held horizontally for a photo? has anyone experimented with this? |
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Location: Madison, WI | Where are those willing to have a serious discussion? Lots of jokers commented... but seriously... I want to learn more about the girth measurement and how to use it... how much can the girth measurment vary? How tight should the seamstress tape be pulled? How do you ensure it is "square"? Do you take it while the fish is in the water, on a bump board, or held horizontally for a photo? has anyone experimented with this?
the joking was a result of the false assumption included in your original question, jlong. combining records with girth measurements is not realistic because of all the inherent measurement errors such as those you just listed. if you want to know how to make the best possible girth measurement for your own puposes, okay, but let's not suggest that there's any possibility of using them to determine records.
if you're interested in it for your own purposes, i think the thing that matters most is consistency. do it the same way every time and you've got a point of comparison across your own fish. as hard as i might try, i know that consistency from one of my own fish to the next is imperfect, so i don't think it's reasonable to believe it will ever be consistently "right" from person to person.
for myself, i've only girthed a handful of fish. i cut a piece of fishing line and measure the out-of-water girth at point centered between the pectoral fins and pelvic fins (the front two sets on bottom of fish). i try to make sure the line is vertical or at a 90-degree angle to the fish's length. i pull it snug enough to remove any slack line without squeezing the fish. it that right, is that wrong? i dunno, don't care all that much, but i'm consistent. and it gives me a point of reference to at least chuckle when i hear people claim 27" girths...
and of course there are lots of ways to measure fish size: weight, volume, length, girth, head/body ratio, etc. each tells you something, but none of them tell you everything. but since weight is the historic measure for records, i suppose that'll continue to be important. personally, i think it would be great if record-keeping bodies would certify live-weight scales at key access points on fisheries with the potential for record-class fish.
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Location: minocqua, wi. | volume of a symmetrical object
vs. volume of a variable object ...
yah, do the math all the time, not usually on fish.
lambeau = yup |
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Location: minocqua, wi. | the calculation you are showing would use the 800 to average mass density ... the reason it's inaccurate with big fish is that it's derived from a limited volume calculation and no longer represents the shape (volume). if displacement (real volume) is used and tied to a mass-density target you would have a much more accurate number if you chose to want something other than certified weight. |
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| I'll guarantee some of you guys got your books knocked out of your hands a LOT at school.
It's like I said on the other site. Until you go to measuring bone on a dead fish it NEVER will be totally accurate. Any fish that is measured and then released is truly only an estimate of the girth and length because of all the variables. And no, I'm not suggesting we kill any fish.
jlong, to your question about an accurate girth, I have no idea if there's a good answer to it. lambeau did a pretty good job.
I've gotten to the point that I do not score my bucks anymore and rarely measure any of my fish. I shoot what I shoot and I catch what I catch.
StormyK
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Posts: 1937
Location: Black Creek, WI | There are people out there who are chasing the record. I'm certain there are boats floating around Mille Lacs in November with numbers in mind. If they have the length and girth needed to generate a calculated weight that exceeds the "record"..... it's likley the fish will end up dead. Whether admittedly or under the guise of being deeply hooked. No doubt... some fish will get whacked and fall short of the record. If this scenario exists.... perhaps generating some dialogue on the internet regarding these weight calculators and all the assumptions and errors involved.... we may educate a few people so smart decisions can be made. And dare I say save a fish? Even if we aren't talking about chasing the record or the potential demise of a foish, there are many musky anglers using these calculators today. They might be chasing a goal such as catching a 30 pounder. Are these calculators "tempting" people to exaggerate their measurements to avoid disappointment? Just look at how many critics we have on these boards when someone posts a length and girth measurement with their photos. Considering all of my above comments, I can't find much in past discussions here regarding how to properly take a girth measurement. And I certainly don't see much explaining the formulas. That is what I'm interested in here. We went through the evolution of obtainging decent length measurements around the same time C&R became immensely popular. Floating measuring stic"ks, to cradles, to some really accurate and "good for the fish" bump boards we see today. As girth measruements become more widely used.... why aren't we seeing ways to improve the measurement? If its bunk... then why is it still being used? |
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| It's a lot easier and more accurate to simply buy a very good scale, I spent $100 on one and have weighed a 40 lb dumbell with it and it's off by 2 ounces.
I think I'm fairly accurate girthing fish, have done so on a number of occasions and have weighed them, they came out + or - within 2 lbs of the formula. Some fish have big bellies but don't carry the weight, some are thick head to tail. Lots of variables. It's fairly easy to get an accurate girth on a fish lying on a bumpboard, not sure why some are having a hard time with it?!
Reality is so very few fish in MN are caught that approach/exceed the record.
If you think you want the record, get a scale! |
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Location: Smith Creek | Hi, my name is Flambeauski. If you're anything like me you've always wondered how to measure the countless world record class muskies you release. You've tried measuring them. You've tried weighing them on a bathroom scale. You've even tried photoanalysis. What a mess!
No more!
Now, for the first time ever, you can own the Muskie Volumizer! Simply enter the fish in the Volumizer and it's patented design will tell you the exact volume! No more of your friends calling you liar. No more fish slime on your wife's sewing tape. And if you order now, we'll throw in the Boga Brush, the only product on the market that subdues the fish and cleans their teeth. Just pay the extra processing and handling.
Hurry! Supplies are limited!
Edited by Flambeauski 1/3/2013 1:14 PM
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Location: minocqua, wi. | LxG and a random density number work if you are measuring a 5' 2"x6" ...
as long as you don't mix the maple with the pine |
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Location: Elk River, Minnesota | jlong - 1/3/2013 11:56 AM
I agree, Bytor. Where are those willing to have a serious discussion? Lots of jokers commented... but seriously... I want to learn more about the girth measurement and how to use it. L x G x G / 800 is a volume equation, right? I'm assuming the 800 is a constant derived from all the conversion factors involved? Has anyone done the math themselves and are willing to explain all the assumptions made? Secondly, any error in the girth measurement is multiplied exponentially... in comparison to an error in the length. If length can vary by up to an inch pending whether you measure with an open tail or pinched tail... how much can the girth measurment vary? How tight should the seamstress tape be pulled? How do you ensure it is "square"? Do you take it while the fish is in the water, on a bump board, or held horizontally for a photo? has anyone experimented with this?
Hiya,
Jason you are correct in the equation being a volume measurement as you are basically multiplying 3 dimensions (Length, radius and radius) as it pertains to a cylinder (where the girth acts as circumference). The 800 is basically a constant that was found from using measurements of many many fish with known weights which, when you use the measurements of your fish would put you pretty close to the actual weight of the fish. the 800 itself would include a calculation that converts girth^2 to a radius^2 so it acts like multiplying 3 dimensions (length width and height). then the other portion of the 800 is a constant of variation that converts volume to weight). This equation assumes mass density and has variables in it as well such as the ones mentioned: how do you calculate accurate girth? Where do you calculate girth? How many times do you measure? Average the girths, etc?
No matter what goes on here, there will always be some sort of error involved whether you measure by volume then calculate based upon a given constant or just by the L x G x G/800.
Could it be more accurate if we used a uniform density measurement? Maybe...but that would require accurate measurement for mass and volume of many many fish. Volume being the measurement we would not have for most of those fish. If people would be willing to try something such as measuring volume and weight of their fish caught (all sizes) I would be willing to put the numbers together to see what comes out of it. I'm just a little mathematically challenged...
Steve |
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Posts: 1290
Location: Hayward, Wisconsin | jlong wrote: “Where are those willing to have a serious discussion? Lots of jokers commented... but seriously... I want to learn more about the girth measurement and how to use it... how much can the girth measurment vary? How tight should the seamstress tape be pulled? How do you ensure it is "square"? Do you take it while the fish is in the water, on a bump board, or held horizontally for a photo? has anyone experimented with this?
LR: First of all Mr. Long, I am “serious”, but perhaps not so much when it comes to measuring the girth of fish intended to be released and then trying to apply a formula to them based on “dead fish”. My mantra is and has been for many years now; “If you don’t weigh it, you shouldn’t say it.” lambeau pretty much summed it up when he said;…”the joking was a result of the false assumption included in your original question, jlong. combining records with girth measurements is not realistic because of all the inherent measurement errors such as those you just listed. if you want to know how to make the best possible girth measurement for your own puposes, okay, but let's not suggest that there's any possibility of using them to determine records.”
lambeau’s comment: “if you're interested in it for your own purposes, i think the thing that matters most is consistency. do it the same way every time and you've got a point of comparison across your own fish. as hard as i might try, i know that consistency from one of my own fish to the next is imperfect, so i don't think it's reasonable to believe it will ever be consistently "right" from person to person. for myself, i've only girthed a handful of fish. i cut a piece of fishing line and measure the out-of-water girth at point centered between the pectoral fins and pelvic fins (the front two sets on bottom of fish). i try to make sure the line is vertical or at a 90-degree angle to the fish's length. i pull it snug enough to remove any slack line without squeezing the fish. it that right, is that wrong? i dunno, don't care all that much, but i'm consistent. and it gives me a point of reference to at least chuckle when i hear people claim 27" girths…”
LR: Can’t say it ever been better said and I agree with his “claim 27” girths” comment! However, lambeau’s comment: “personally, i think it would be great if record-keeping bodies would certify live-weight scales at key access points on fisheries with the potential for record-class fish.” is unrealistic on large water bodies like the St. Lawrence River. Just won’t happen and the issue of transport of large fish would certainly get ugly!!
jlong continued: “There are people out there who are chasing the record. I'm certain there are boats floating around Mille Lacs in November with numbers in mind. If they have the length and girth needed to generate a calculated weight that exceeds the "record"..... it's likley the fish will end up dead. Whether admittedly or under the guise of being deeply hooked. No doubt... some fish will get whacked and fall short of the record. If this scenario exists.... perhaps generating some dialogue on the internet regarding these weight calculators and all the assumptions and errors involved.... we may educate a few people so smart decisions can be made. And dare I say save a fish? Even if we aren't talking about chasing the record or the potential demise of a foish, there are many musky anglers using these calculators today. They might be chasing a goal such as catching a 30 pounder. Are these calculators tempting" people to exaggerate their measurements to avoid disappointment? Just look at how many critics we have on these boards when someone posts a length and girth measurement with their photos…As girth measruements become more widely used".... "why aren't we seeing ways to improve the measurement? If its bunk... then why is it still being used? ”
LR: Again, and if this is indeed the case, then these boats should be carrying certified scales and FORGET about trying to “estimate” a fish’s weight by using the formula! It takes no longer to weigh a muskie than it does to girth it; weighing methods, and several have already been discussed, is what you should be worried about, not “girthing”.
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Posts: 1937
Location: Black Creek, WI | Recors are being broken. Quite regularly too. In the past 10 years, how many have been "updated"? Michigan's record has been broken several times in the past 2-3 years. And.... I'm only using State and World records as an example here. Especially when there are a fair number of released fish each season with record setting POTENTIAL. So what is the new "standard" for measuring up our catches? Do we need to go to extremes and truly chase the record and kill our catch.... or go the other way and become SOUL fisherman who could care less about the "numbers" since all fish are equals? |
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Posts: 1937
Location: Black Creek, WI | Lenth measurements have merit since Daily Bag Limits are based on them. Weight measurements have merit as RECORDS are based on them. So... my ORIGINAL question was this, "What is the purpose of taking a GIRTH measurement?" |
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| or buy a scale and learn how to weigh it in the net. Problem solved.
JLong, are you simply trying to figure out what your big one from Vermilion weighed? If so, the weight calculator at the bottom of this site is pretty accurate on MN fish. It will get you close enough anyway. |
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Posts: 1937
Location: Black Creek, WI | Kerplunk... if I wanted to know the weight... I'd have weighed it. But... I did attempt to take a girth measurement out of curiosity and while doing it, it became obvious that I have virtually NO EXPERIENCE with taking such a measurement. Thus, I"m wondering just what is the value of a girth measurement? And... if they are a necessary evil, how can I improve my next measurement? I see posts titled here "Potential Record" based on a weight calculator that uses Length and girth measurements. When posts occur claiming a new world record.... length and girth measurements are usually presented as evidence. As a result... I really like Ramsell's remark "If you didn't weigh it, don't say it" |
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Location: Smith Creek | I guess if you want a replica made then get the girth. There's no such thing as a state record that was released.
Technically every 35" fish caught is a "potential" state record.
Edited by Flambeauski 1/3/2013 2:37 PM
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| "if you didn't weigh it, don't say it", to some degree sure, but,
I would think most guys that have caught and been in the boat with big fish aren't out there saying their fish weighed 42.97 lbs based off the formula. ie, if it was a solid 55 x 25 I would think most would say it was a low 40 lber. Which it most certainly was. Just like there are guys that don't measure their fish, they've caught enough to not care per say, but when they catch a fish that was high 40 incher, isn't it fair enough to say it was an "upper 40 incher", they didn't measure it, are people going to knock that too? I would hope not.
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