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Sex change of hatchery produced Amphiprion ocellaris: Influence of mating system removal on gonad maturation and nesting success

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Title Sex change of hatchery produced Amphiprion ocellaris: Influence of mating system removal on gonad maturation and nesting success
Not Available
 
Creator Madhu,Rema
Madhu,K
Venugopal,K M
 
Subject Amphiprion
gonad maturation
sex change
 
Description Not Available
The influence of gonadal maturation and nesting success of the anemone fish Amphiprion ocellaris
was analyzed through mating system removal. Four experiments viz., (i) Sex change of active male
to female in the absence of active female, (ii) Juveniles in the presence of a functional male that was
changing sex from male to female, (iii) Juvenile in the presence of a functional female, and (iv)
Same length group juvenile fishes (total length: 50 mm) without the presence of adult fishes, were
carried out. The gonad of male in experiment (i) showed first perceptible sign of sex inversion after
1 to 2 weeks. After 25 weeks the testicular zone almost disappeared and the gonad looked like maturing
ovary with perivitellogenic oocytes and oocytes at various stages of development. The gonad of
juveniles in the second experiment showed increased testicular development after 23 to 24 weeks, and
testicular area became clearly discernible after 30 weeks. In the third experiment, the gonad of juvenile
completed its spermatogenesis after 15 to 16 weeks and showed well-developed testicular zones. In
the fourth experiment, the gonad of largest fish showed development of ovarian part after 24 weeks
with oogonia and oocytes at various stages, and degeneration of testicular tissues. The observation of
nesting success in the above experimental groups showed that spawning was obtained in the third group
after 4 months of association; and after 12 to 18 months in the first and second groups, and after 20
to 24 months in the fourth group. The present study shows that in the absence or disappearance of
adult female, the active male changes sex to female within a period of 25 weeks. The study also confirms
that in the clownfish A. ocellaris, the largest and socially dominant fish in a host sea anemone
(Heteractis magnifica) is generally female, whose gonads are functional ovaries with remnants of
degenerated testicular tissues. The second largest fish in the same group is an active male and has
gonad that are functioning testis but also possess non-functioning or latent ovarian cells (ovotestis).
If the dominant female dies or is experimentally removed from the "queue", the male not only changes
sex but also grows at an accelerated rate, and the juveniles also grow faster to become male and fill
the size gap of the social group. This adaptation allows continuous reproduction. It is found that social
structure plays an important role on the sex changing mechanism.
Not Available
 
Date 2021-09-16T05:25:56Z
2021-09-16T05:25:56Z
2010
 
Type Article
 
Identifier Not Available
Not Available
http://krishi.icar.gov.in/jspui/handle/123456789/62691
 
Language English
 
Relation Not Available
 
Publisher MBAI, Cochin