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The problem of age-determination in the Indian Mackerel, Rastrelliger kanagurta, by means Of scales and Otoliths

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Title The problem of age-determination in the Indian
Mackerel, Rastrelliger kanagurta, by means
Of scales and Otoliths
Not Available
 
Creator Seshappa,G
 
Subject age-determination
Indian
Mackerel
Rastrelliger kanagurta
scales
Otoliths
 
Description Not Available
• The study of the scales of Rastrelliger kanagurta (Cuvier) collected from different
centres during the period 1955-67 and 1969-70 showed that at all centres specimens below
21 cm in total length were without scale-rings; a small percentage of specimens in the
• 21-22.9 cm group showed rings, while a large percentage among those above 23 cm total
length showed the rings in all the centres, this percentage being the smallest (63.1 %) at
Calicut and largest (94.3%) at Karwar. Two rings occurred frequently in specimens
above 25 cm and up to four rings occurred in the very large specimens of Vizhinjam and
Mandapam, but in these large specimens reading of the rings was difficult as they frequently
became faint and obscured as a result of the thickening of the scales subsequent
to the ring-formation. The scale-rings seem to be formed as a result of a physiological
strain on the fish during the process of growth and ripening of the gonads and also spawning.
When clear rings were not noticed in mackerel with gonads in advanced stages,
there were thin margins, which indicated the beginning of ring formation. The otoliths
did not show any annuli that could be used for age-determination.
It is suggested that the mackerel reaches a total length of 11-15 cm by the end of
the first year, 21-24 cm by the end of the second year, 25-27 cm by the end of the third
year, and 28-29 cm by the end of the fourth year of life.
Not Available
 
Date 2021-08-10T12:01:45Z
2021-08-10T12:01:45Z
1969
 
Type Article
 
Identifier Not Available
http://krishi.icar.gov.in/jspui/handle/123456789/54517
 
Language English
 
Relation Not Available
 
Publisher CMFRI/ICAR