Hi

I think there is a simple method to do that it can be determined by counting the number of paired summer/winter growth zones.

regards

In the plant kingdom, tree rings indicate annual growth increments. In the animal kingdom, probably the most well-known patterns visible externally are on the shells of molluscs and tortoises. However, other groups have also been shown to produce annual or daily growth increments: these include some coral, cricket and starfish skeletons, and the teeth of some mammals. However, fish produce growth increments in various calcified structures, most notably in their otoliths (or 'ear stones'), but also in scales, spines, vertebrae and other bones.

Otoliths are paired calcified structures occurring in the heads of all bony fishes - they do not occur in the cartilaginous sharks or rays. Like the human ear drum, otoliths are part of the fish's sensory and balance system, and the name 'otolith' comes from two Greek words meaning ear and stone. Otoliths are mainly calcium carbonate (limestone) with a small component of non-organic trace elements and protein molecules.

It is estimated that well over a million fish are aged each year worldwide, highlighting the importance of age information in fisheries science. Fish ageing studies are either based on annual or daily growth. Annual ageing studies are the most common because they provide information on fish productivity and population structures. Daily ageing, using otolith microstructure, is used mainly in studies of young fish

hi 

http://msue.anr.msu.edu/uploads/resources/pdfs/Determining_the_Age_of_Fish_(E1774).pdf

Dear,Dr.

I think that Fish ageing studies are either based on annual or daily growth. Annual ageing studies are the most common because they provide information on fish productivity and population structures. Daily ageing, using otolith microstructure, is used mainly in studies of young fish

Thanks

can be determined by counting the number of paired summer/winter growth zones. One pair of such zones is called an annulus (plural, annuli). Thus, the process of ageing fish is similar to finding the age of a tree by counting rings in the wood.

For different species of fish, different structures are used to determine ages. In general, annuli from these various structures are visible under a low-power microscope. Scales are used for some species. On these structures, winter zones appear as regions where the ridges on the scale are closer together. Scales are easy to sample and can be impressed in plastic for long-term storage. If scales can’t be used, otoliths (located inside the skull) may be used instead. In otoliths, the color of the zones differs, resulting in alternating opaque and translucent bands. Some otoliths are clear enough for these zones to be seen from the surface of the otolith and may be aged whole; otherwise, the otolith must be thinly sliced in order to see the zones. Other structures used for ageing include vertebrae or fin rays.

The choice of age structure for a species depends on which structure most accurately reflects the true age of the fish, has the clearest zones, and has the most cost-effective preparation method. For each species, a validation study is conducted to demonstrate that the chosen structure yields accurate ages. This entails determining the position of the first annulus and proving that the zones are laid down exactly once per year. Common validation techniques include tag/recapture studies, including marking with oxytetracycline or other chemicals, back-calculation, marginal increment analysis, and radiometric/isotope analysis.

hello dear .. can by by counting the number of paired summer/winter growth zones. One pair of such zones is called an annulus (plural, annuli). Thus, the process of ageing fish is similar to finding the age of a tree by counting rings in the wood.

How is the age of fish determined?. Available from: https://www.researchgate.net/post/How_is_the_age_of_fish_determined [accessed May 11, 2017].

HI

I AGREE WITH DR.NOOR

i agree with Dr. noor

Hi

I think there is a simple method to do that it can be determined by counting the number of paired summer/winter growth zones.

regards

Hi

Good question . I don't know about that.

I hop to know from your answers.

Thanks with regards

Hello Dr. Aseal

The age of Fish is determine by counting the number of annuli (rings) on a scale provides the fish age and the spacing between rings is proportional to the growth of the fish. For some examples and uses of scale aging you can go to "Fish scales tell a story..." from the Delaware Division of Fish & Wildlife.

Hi

I agree with Dr. Furqan

can be determined by counting the number of paired summer/winter growth zones. One pair of such zones is called an annulus (plural, annuli). Thus, the process of ageing fish is similar to finding the age of a tree by counting rings in the wood.

Hi

Good question.

The best wishes.

thanks alot