Dynamics of gonadosomatic index of fish with indeterminate fecundity between subsequent egg batches: application to Japanese anchovy Engraulis japonicus under captive conditions

The gonadosomatic index (GSI) is widely used as a simple measure of reproductive capacity, but its validity has often been questioned. This study showed the inter-spawning variation in the predicted GSI of Japanese anchovy using the gravimetric oocyte packing density method. Time course sampling sho...

Full description

Saved in:
Bibliographic Details
Published in:Marine biology 2013-10, Vol.160 (10), p.2733-2741
Main Authors: Yoneda, Michio, Kitano, Hajime, Selvaraj, Sethu, Matsuyama, Michiya, Shimizu, Akio
Format: Article
Language:English
Subjects:
Agnatha. Pisces
Anchovies
Animal and plant ecology
Animal reproduction
Animal, plant and microbial ecology
Biological and medical sciences
Biomedical and Life Sciences
engraulis japonicus
Fecundity
Females
Fish
Freshwater & Marine Ecology
Fundamental and applied biological sciences. Psychology
Life Sciences
Marine
Marine & Freshwater Sciences
Marine biology
Measurement
Microbiology
Oceanography
Original Paper
Sea water ecosystems
Sexual behavior
Spawning
Synecology
Vertebrates: general zoology, morphology, phylogeny, systematics, cytogenetics, geographical distribution
Zoology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The gonadosomatic index (GSI) is widely used as a simple measure of reproductive capacity, but its validity has often been questioned. This study showed the inter-spawning variation in the predicted GSI of Japanese anchovy using the gravimetric oocyte packing density method. Time course sampling showed that final oocyte maturation and subsequent ovulation occurred from afternoon to evening on the day of spawning. Oocyte in vitro assay, however, suggested that the timing of the spawning could be predetermined by midnight the day before spawning. Models predicted that the GSI of a female just after spawning gradually increases until the completion of germinal vesicle breakdown, after which it dramatically rises by 24–53 % per hour within a few hours of the onset of ovulation. This indicates that the predicted GSI of a female increases by 3.5 times within about 19 h before ovulation, even if the relative batch fecundity remains constant.
ISSN:0025-3162
1432-1793
DOI:10.1007/s00227-013-2266-9