age of fish

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ingy

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is there anyway you can tell the age of fish is it by scale rings etc anyone know
 
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paul williams 2

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I believe that is a way of estimating the age of a fish ingy.......
 
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The Monk

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yes as a guide thats the way it is done, simliar to a tree and the growth rings!
 
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Ron 'The Hat' Clay (ACA)

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I have a feeling it's not all that accurate mate and depends on how often a fish spawns.

Some species do not spawn every year.
 
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The Monk

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yes it is flawed and only shows calcium levels I think? its a long time since I read up on that sort of thing?
 
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paul williams 2

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I once sent a scale of a large Zander to Nev F.... he gave me an estimation of the fishes age from it.

I think it is exactly as Nick says, just like a tree....eg you can tell good fast growth years from hard slow growth years.........but i'm only drawing from memory not solid fact.
 
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The Monk

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yes it acts only as a rough estimate Paul, poor dietary conditions, deficiencies and illness may not show calcium growth patterns as such and need to be interpreted against other information
 
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The Monk

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Investigating the age and life span of fishes is especially difficult, if not impossible, from only brief observations in the wild. Fortunately, individual fishes keep a permanent record of their life history in some of the hard tissues of their bodies. As a fish grows, its scales must grow as well in order to keep its body covered. If a scale is lost or removed, a new one will replace it. The process is similar to the way a tree grows, but while trees add one ring per year, a fish scale may gain many rings (two, three or up to 20) in a single year.
 
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ED (The ORIGINAL and REAL one)

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Can't you just ask it for its birth certificate
 
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john conway

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You can get a reasonable estimate of a Chub's age by reading the rings on a scale taken from the shoulder of the fish. However, it's only good up to the age of 11 or 12. You also have to be careful that you are not reading a replacement scale from ones that?s been lost. Like a tree you can also tell the hard times and the good from the distance between rings. The Chub Study Group has done quite a bit of work re the age of chub relative to weight to determine the potential of a water re big Chub.
 
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Cakey

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if you cook a fish then cut it in half then you can count the rings
 
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Phil Hackett The ostrich pie hater

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A more accurate aging can be gained by using the operculum bone, but the fish has to be dead to gain it. (Goldspink C. Circa 1975 pers com.) Not practical to use on fish that are going to be returned. Whether this still hold true or not I don?t know. But the good Dr Clough who visits this site would know.
 
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Cakey

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The choice of an age determination method for a given species involves deciding on an appropriate aging structure (scales, otoliths, vertebrae, spines, etc.) and processing method (impressions, thin sections, etc.) for that structure. The next step is validation, in which the marks used to age fish are verified to occur once per year and at approximately the same time each year. Common validation techniques include direct methods such as tag/recapture studies, including marking with chemicals such as oxytetracycline, calcein, and others; and indirect techniques such as back-calculation, marginal increment analysis, edge progression analysis, length frequency-year class progression analysis, radiometric/isotope analysis, elemental analysis, and others.
To age a fish, an age reader must identify the annual growth marks (annuli) on the structure chosen. In temperate waters, fish growth is fast during the summer months when water temperatures are warm, and slow during the cold winter months. A year of growth is defined as one summer zone plus one winter zone. These zones are identified on scales as areas of wide (summer) and narrow (winter) circulus spacing. On otoliths, these zones are identified as alternating opaque and translucent bands when viewed microscopically.


In 1988, the Fishery Biology Program developed and published a set of detailed descriptions of the age determination methods we routinely use. These descriptions are being updated and will be reprinted here in their entirety. The descriptions are designed for use primarily by fishery biologists and professional age readers and students but may be of general interest.
 
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Cakey

Guest
also

Fish have bones in their heads called otoliths (oto? meaning ear and lith? meaning stone). These bones help the fish to keeping its balance in the water. When an otolith is removed from a fish, sectioned into thin slices and viewed through a microscope, it reveals a pattern of light and dark concentric rings.
 
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Fred Bonney

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The things that happen to you, when your on a special diet,eh,Cakey? ;o)
 
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