Fish Scales

[Gray-Catchpole]

ive just been reading some stuf on fishing, and something caught my eye.

 

a 2lb salmon and 40lb salmon have exactly the same number of scales, does this stand for all fish??

[Leon Roskilly]

Gray-Catchpole:

ive just been reading some stuf on fishing, and something caught my eye.

 

a 2lb salmon and 40lb salmon have exactly the same number of scales, does this stand for all fish??

Dunno!

 

What I do know is that (at least on some fish), counting the rings on a fishes scales gives a fair (though by no means accurate) indication of the fishes age.

 

I regularly put mullet scales onto my scanner, and scan in just the scale, at maximum resolution.

 

I then blow it up to A4 size and print it. Then I use a pen to mark the rings.

 

Mullet scales come off very easily, part of their defence mechanism. A seal has a mullet then, no it doesn't - just a mouthful of loose scales!

 

Drives taxidermist barmy, especially if they have never done a mullet before, and have quoted on the basis setting up other fish of similar size!

 

(er, just in case this thread starts to develop along the lines of rights and wrongs of having fish set up, I'm talking road kill only here!!)

 

Tight Lines - leon

[Chris Plumb]

Yes!

 

One of the the ways to conspicuously indentify fish is to count the scales in the lateral line. This doesn't change with the fishes age but does vary from species to species. eg Roach have typically have 38 - 49, rudd 38 - 42, bream 51-60 and so on (I've got the whole list if your interested!!)

 

So scales increase in size as the fish grows. Around the base of each scale new lamellae called sclerites grow all the time, these are discernible as a number of dark and light rings arranged concentrically. They are reminiscent of the yearly growth of a tree. However, individual lamellae do not necessarily represent a year's growth as they may grow irregularly, depending on the fishes rate of growth. But as most fish grow quicker in summer producing broad lamellae and slow down in winter producing narrow ones it IS usually a good rough guide to the fishes age. Similar patterns of alternation in light and dark zones can often be seen in the bones of fish as well.

 

Interstingly examining the scales of a salmon can reveal the number of years spent at sea, in fresh water and the number of times it has returned to spawn.

 

Chris

[phonebush]

True,

except for those species that molt.

Phone

[Newt]

Dang Phone. I know that snakes and lizards molt. Never knew there were fish that did though.

 

Can you name any?

[Gray-Catchpole]

very interesting cheers chaps

 

the tree factor had occured to me, i also read that examining the scales can tell the experts the actual river they come from.

[Gray-Catchpole]

mmmm prey tell phone

[RollingPinBoy]

In research i have found that different Barbel can vary in scale counts with some as low as 56 along the lateral line and others up to 65. You will also find that girth (dorsal to pelvic fin) will vary also. Ray Walton

 

[ 18 April 2002, 10:12 PM: Message edited by: RollingPinBoy ]

[Vagabond]

Before you all get too excited about telling the age of a fish by counting growth rings on the scales, consider this .....

 

Fish eventually reach a point where they cease to grow very much - if the fish doesn't grow, its scales don't grow ( a mature fish might even lose weight, and if so, the edges of the scales become eroded)

 

If the scales don't grow, then they won't be showing extra growth rings, will they?

 

Note too that if a fish loses scales, it grows new ones, called regeneration scales - which show no growth rings at all.

 

Scale rings will only tell you the rate of growth in the years of a fish's life up to maturity - very useful information, provided you are aware of its limitations.

[phonebush]

No, I don't know of any but I'm sure it's true.

Phone