Fish Scales

[Vagabond]

I'd agree with that Alan - especially with perch. But fish can't swim away if the earbone has been removed - whereas they can survive the loss of a scale.

 

What the scales will show pretty well (in some species) is growth rate in the early years - eg scales from common carp around (say) 2 to 10 lb from a reasonably good water should show something like its true age - and hence its growth rate.

 

OTOH the bigger fish might have ceased growing, so you could only deduce a minimum age, not the true age, from the scale - and of course you couldn't work out a growth rate from that.

 

....and surely Alan, if a bigger fish stops growing, won't its otoliths (ear bones) stop growing too???? just as its scales (and every other part) stop getting bigger ??

 

So you are back where you started on difficulties in measuring growth rates by measuring bits of any fish that has reached its "mature" weight. Unlike trees, fish can actually lose weight and girth - so the tree-ring analogy doesn't help.

 

Have a look at Kevin Cliffords "Redmire Pool" (or any well-organised carp syndicate's log-book)

 

Lots of repeat captures over the years with fluctuating weights - these would not correlate very well with any attempt to measure ages by scales, opercular bones, otoliths or whatever.

 

[ 20 April 2002, 09:26 PM: Message edited by: Vagabond ]

[RollingPinBoy]

Grey- From experience from on the bank and not read from books, as most scale reading/counts references come from old books often copied from even older books and not neccessarily accurate or as some say, 'a true science. I found that the barbel scales start to develop from birth although they may not be visable at the time of hatching. That i found out when visiting the E.A Calverton fish farm.

Back on the bank i would say that the barbel total scale count is there from a very young age and are there for life. They do lose scales and re-generate a plate, which grows very quickly to cover the wound, which is blank and shows no rings until the wound is covered. Once it has covered the wound, it then proceeds to grow another plate underneath and then carrys on outwards and develops growth rings as it reaches the edge, as the fish grows and increases in size, ie: to cover more flesh. If the wound is large where a number of scales are lost in close proximetry, thay may grow back one large one, instead of re-generating a larger number. Some can vary in shape also. Each scale is made up of individual plates, ie: a five year old barbel would have five plates laid on top of each other starting from the 1st year in the middle. ie: like a stepped pyramid. On some other species such as chub, you can split the scale plates to age, but on barbel, it is more difficult. Don't believe all you read in books. Some is accurate but some is not. I once questioned some NRA guys back in the 80's, when we were involved in the King's Weir barbel Tumours/Cancers and Blindness research on the River Lea. The NRA stated that the majority of barbel with tumours and blindess were old fish with an age of 9+ up to 12+ years, according to ageing by scales. They assumed that barbel only lived for up to 15 years. I knew that was not the case and that these were only young to middle aged barbel and there was a problem, or it could have been a cover up. On another occassion when asking NRA how they aged fish by a scale, they told they told me that the new years growth ring was on the inside. They new nothing about plates and were reading growth rings back to front, which is wrong as the scale ring are wider from 1-7 years, showing rapid growth when the fish is younger, then narrower as the fish reaches it's full skeletal growth and gets older. There is loads more which i have found that includes identyfying males from females and true potential from a young age according to scales. These are my own findings and opinions. I am writing a barbel book at present and these findings will be included and lots more technical stuff. Ray Walton

 

[ 20 April 2002, 11:26 PM: Message edited by: RollingPinBoy ]

[Gray-Catchpole]

the reply`s ive hade from this post have been great, email has hit a new high, thank you all for you help, i know not alot , but iv`e learnt thousands. as usual.

 

ray thanks for the info, again i have no real experience with barble, but i had a feeling they grew past the age of 20, wonderfull stuff chaps cheers.

[Bretty]

I think your all crazy a 2lb Salmon will say 2lb on the scales and a 40lb salmon will say 40lb it's to do with how heavy it is you see!

 

And you don't cut a fish in half and count the rings to find out it's age, Thats trees!!!!! God where would you be without me on this forum

 

As for mullets they went out with the flat top!!!

 

Okay you guessed it i don't know! :confused:

 

Bretty

[Gray-Catchpole]

ive only one argument with that bretty, flat tops are still cool, had one for many years, i fluctuate between that and the good old mohawk, but i wont argue, dont want me spikes snapped

[Chris Plumb]

quote:

---

Originally posted by Vagabond:

[QBYes - didn't mention that

- cos I proof-read DM's original contribution

 

QB]

---

Ah - I thought DM might be a contemporary of yours when I saw he was a member of The British Ichthyological Society.

 

C.

[Vagabond]

RollingPinBoy:

 

1/ when asking NRA how they aged fish by a scale, they told they told me that the new years growth ring was on the inside............. and were reading growth rings back to front,

 

2/ true potential from a young age according to scales.

1/ - but I believe it !

 

2/ YES - that's the most useful thing you can get from scale reading. What you usually can't get is an absolute age for older fish.

 

You are spot on re regeneration scales.

 

I might add I have done quite a few scale readings, but have not come across any deviation from the ranges now published by Peter Maitland (Hamlyn Guide to Freshwater Fish of Britain and Europe)