Barbel weight vs length. Etc etc

[Tim Marks]

Has anybody (or one of the barbel groups) ever bothered to try and make a scale of barbel weight vs length (and maybe girth)?

Ive never bothered to measure any of my (few) big fish - so have little real idea of their actual dimensions….but I do know the weights !

Somebody has just asked me as they have caught a decent fish and not weighed it.

A quick google search (German data) suggests:

75cm, 29” - 9.8Lb
80cm, 31” - 11.8 lb
85cm, 33” - 14.2 lb
90cm, 35” - 16.9 lb

That is 1/10 of pounds, rather than ounces AND obviously ignores girth -which can make a big difference.

Ive used complicated formula for estimating big saltwater fish (eg tarpon) - and they are reckoned to be quite accurate. I’ve caught lots of bonefish (which are shaped very like barbel) and their girth makes a big difference to the actual weight.

I also remember from my Tenchfisher days that we used to reckon a ‘7’ from Sywell was roughly 2” shorter than a Johnson’s (Kent) fish of similar weight.

Any thoughts, or data on 12-15 lb fish much appreciated.

I know it’s impossible to estimate weight from a photo…….

 

[Richard Isaacs]

Has anybody (or one of the barbel groups) ever bothered to try and make a scale of barbel weight vs length (and maybe girth)?

Ive never bothered to measure any of my (few) big fish - so have little real idea of their actual dimensions….but I do know the weights !

Somebody has just asked me as they have caught a decent fish and not weighed it.

A quick google search (German data) suggests:

75cm, 29” - 9.8Lb
80cm, 31” - 11.8 lb
85cm, 33” - 14.2 lb
90cm, 35” - 16.9 lb

That is 1/10 of pounds, rather than ounces AND obviously ignores girth -which can make a big difference.

Ive used complicated formula for estimating big saltwater fish (eg tarpon) - and they are reckoned to be quite accurate. I’ve caught lots of bonefish (which are shaped very like barbel) and their girth makes a big difference to the actual weight.

I also remember from my Tenchfisher days that we used to reckon a ‘7’ from Sywell was roughly 2” shorter than a Johnson’s (Kent) fish of similar weight.

Any thoughts, or data on 12-15 lb fish much appreciated.

I know it’s impossible to estimate weight from a photo…….

Certainly from my own perspective length alone gives very little indication as to what the weight would be simply because their frames vary a lot and time of year obviously plays an enormous part in it so I really don’t know where these German figures have evolved from.

2 examples here both October fish caught on the same river Less than 50 yards apart.
The difference in weight is 5oz and the shorter fish is the heavier

 

[Mark Pevy]

Certainly from my own perspective length alone gives very little indication as to what the weight would be simply because their frames vary a lot and time of year obviously plays an enormous part in it so I really don’t know where these German figures have evolved from.

2 examples here both October fish caught on the same river Less than 50 yards apart.
The difference in weight is 5oz and the shorter fish is the heavier View attachment 24757View attachment 24758

Like the way your boy isn't staring at the fish like a bloody carper

 

[Tim Marks]

Certainly from my own perspective length alone gives very little indication as to what the weight would be simply because their frames vary a lot and time of year obviously plays an enormous part in it so I really don’t know where these German figures have evolved from.

2 examples here both October fish caught on the same river Less than 50 yards apart.
The difference in weight is 5oz and the shorter fish is the heavier View attachment 24757View attachment 24758

Thanks Rich; just as I thought the girth is where the weight goes on.

Are we allowed the know the rough weights of those fish please ?

 

[Richard Isaacs]

Thanks Rich; just as I thought the girth is where the weight goes on.

Are we allowed the know the rough weights of those fish please ?

Absolutely. My boys is 13,07 and mine was 5 oz lighter.

 

[Richard Isaacs]

Like the way your boy isn't staring at the fish like a bloody carper

That’s a bad example….. I don’t often look at them at least I wasn’t staring at it’s tail.

 

[Alexander Shepherd]

Absolutely. My boys is 13,07 and mine was 5 oz lighter.

When does your son start take guided bookings , his Dad seeems a bit out of the loop catching wise. Has he a price list yet ? I expect his Dad to be cheaper as a lower hit rate . No offence intended, just highlighting the facts. PS your feeders are A1 but I’m probably barred now.

 

[Richard Isaacs]

Dad seeems a bit out of the loop

Oh charming! Thanks a lot

 

[Russ Fowlkes]

Worth also considering the flow on a rive? You only have to look at the different length to weight ratios of carp and pike from still waters vs. rivers? The same logic would indicate a fast flowing river would have longer fish per pound than a slow running river.

 

[Paul Rogers]

This question is bit of a quandary. I don't believe it has anything to do with flow etc; the answer would lie as it does with humans, some are fatter, taller than others. The images below, are two fish from the same piece of water. The first one was 34 inches long at 16lb 14oz in 2016. The second fish was only 31.5inches long, and weighed 17lb 9oz, on it's last capture in 2018. The picture used was from a previous capture three years before, as a better picture, she still was the same length with less of a girth weighing 15lb 15oz. And before anyone says it has the same damage on the pectoral fin, I know but it appeared to be a common defect on that particular stretch of river. I have photos of plenty of other fish from here showing the same.

 

[Chris Jones]

I give little credence to length/weight conversions. There may be some value with regard to the individual river that such data is collected, but that diminishes rapidly with distance and dissimilarity of the rivers. However, as populations get increasingly genetically homogenous, we may end up with less variance due to Calverton stocking. The differences will then be squarely down to flow rates, temperatures and food availability.

The reality is that I do not expect conversion tables, often based on southern river data, to have any relevance to the Dales Rivers I fish. This applies to the barbel which are usually long and lean compared to those from warmer rivers further south. I'm much more familiar with the discrepancies inherent to grayling conversion tables. Despite fishing for them more than most, it has been decades since I have weighed a grayling over 1lb 12oz from the Swale. Perhaps I'm useless, or just unlucky, but it tends to raise an eyebrow when fly anglers, that don't typically carry scales, regularly claim to be catching 3lb fish. Perhaps the answer lies in the fact that grayling length/weight conversion tables are usually based on southern chalk streams. I often see long fish, but they rarely weigh a great deal.

 

[Richard Isaacs]

I give little credence to length/weight conversions. There may be some value with regard to the individual river that such data is collected, but that diminishes rapidly with distance and dissimilarity of the rivers. However, as populations get increasingly genetically homogenous, we may end up with less variance due to Calverton stocking. The differences will then be squarely down to flow rates, temperatures and food availability.

The reality is that I do not expect conversion tables, often based on southern river data, to have any relevance to the Dales Rivers I fish. This applies to the barbel which are usually long and lean compared to those from warmer rivers further south. I'm much more familiar with the discrepancies inherent to grayling conversion tables. Despite fishing for them more than most, it has been decades since I have weighed a grayling over 1lb 12oz from the Swale. Perhaps I'm useless, or just unlucky, but it tends to raise an eyebrow when fly anglers, that don't typically carry scales, regularly claim to be catching 3lb fish. Perhaps the answer lies in the fact that grayling length/weight conversion tables are usually based on southern chalk streams. I often see long fish, but they rarely weigh a great deal.

Yeah absolutely Chris I certainly believe that an average fish from one river can look very different dimensionally than an average fish from another.
I say average because like in any habitat for any life, oddball’s and abnormalities will always occur.

I absolutely believe river flow makes a difference to both general shape and weight perhaps not so much the general nsl flow but I think the rivers ability to take on extra water probably plays a stronger part.

The swale as you know only needs an over night shower in the dales and it’s up 8ft for a week. This must effect body shape, muscle mass and general appearance as they are living in these conditions Id guess 25-30% of the year. I’m yet to come across a barbel as insane as the creatures inhabiting that river.

Down here on the nene they get an easy life in comparison.
It’s very rich with naturals, the river is up 2-3ft once or twice a year and we have one or two stocky plump girls kicking about.
It’s not known for mega long fish but We have an odd slim Jim too but the majority are well fed stocky girls. Don’t underestimate them mind. They can wake up and smash inferior tackle like it’s play dough when they need to

Having said all that I still think taking a length alone to guess a weight is about as inaccurate as it comes. Same river or not, looks can be deceiving.

 

[Phil Heaton]

Measuring fish seems to be creeping into most forms of angling these days, annoyingly usually followed by a Facebook post asking what people think it weighed. I’ve no problem with anyone doing one or the other, but I’m old fashioned and it’s weight all the way for me.
from my own experience I’ve caught what looked like a big fish of various species that proved not to be on the wheel of fortune (scales) quite a few times so in my mind estimating a weight from length is not reliable.

 

[Paul Gaynard]

Absolutely agree with you Phill, there's only one way to determine the weight of a fish and that's to weigh it, personally I only weigh a fish if I think it may be a double and the number of times I've been wrong is remarkable, there's a chap on our syndicate who insists he can guess weigh almost to the ounce funnily enough the same fellow catches loads of monsters . yeah ok then lol