Results - Details
Search command : Author="Παπαδάκης"
And Author="Ιωάννης"
And Author="Α"
Current Record: 1 of 6
|
Identifier |
000454252 |
Title |
Αναπαραγωγική συμπεριφορά του κρανιού (Argyrosomus regius) σε συνθήκες υδατοκαλλιέργειας |
Alternative Title |
Reproductive behavior of meagre (Argyrosomus regius) in aquaculture conditions |
Author
|
Σιαπάζης, Χρήστος Α.
|
Thesis advisor
|
Παυλίδης, Μιχαήλ
|
Reviewer
|
Μυλωνάς, Κωνσταντίνος
Παπαδάκης, Ιωάννης
|
Abstract |
Meagre (Argyrosomus regius) is a sciaenid species of high commercial interest for
Mediterranean aquaculture. Despite the increase in production, the species exhibits
reproductive dysfunction in captivity, which have been resolved using GnRHa-based spawning
induction and spermiation enhancement protocols. However, the contribution of each breeder
in each reproductive event and the reproductive behavior and the relevant dominance relations
in each broodstock has not been investigated. The aim of this study was to describe the
reproductive behavior and parental contribution of meagre in aquaculture conditions, after
spawning induction with gonadotropin releasing hormone agonist (GnRHa). Two meagre
broodstocks (Group 1 and 2, 2 females and 3 males, each) were utilized for two consecutive
years (Year 1 and 2). At the expected spawning period, reproductive stage was evaluated,
through ovarian biopsies and sperm quality evaluation, and fish were induced to spawn with
GnRHa. Each breeder was externally tagged, and their behavior was monitored using
underwater equipment. Egg production and quality was evaluated and a sub-sample of the eggs
from each spawn was collected for parental contribution analysis. Spawning induction led to
three consecutive daily spawns per group per year. The mean latency period was found 34.1±0.9
h post GnRHa administration. The mean daily relative fecundity (n=2) was 159,743±23,315
eggs kg-1, while mean fertilization success was 83±0 % and 93±0%, for Year 1 and Year 2,
respectively (P=0.036). Parental contribution analysis showed that 77±3% of the eggs were
produced by the same female, while 77±9% of the eggs were fertilized by the same male in
each group for both years. The heavier among male breeders in Group 1 fertilized 68±22% of
the eggs during the two years of the study. In addition to aggressive behaviors, the behavior of
meagre spawners was found to include “trailing” phenomena. In this phenomenon, at least one
male spawner found to spend time following a female spawner. The average tracking time over
the recording period was found to be 197±49 min and the trailing phenomenon was found to
occur on average 64±44 times. The behavior of the meagre breeders was found to include
phenomena of "clinging" and group swimming of all male spawners towards a female
("darting"), the "darting" phenomenon increased during the second breeding season. All
reproductive events (spawning) were found to occur after sunset, with one exception. Each
reproductive event was found to involve one female while the participating males were one up
to the total number of male spawners in the group. The mean duration of the reproductive event
was found to last 0.91±0.06 min and included the attachment of male spawners to the female,
group swimming and simultaneous release of gametes. Finally, behaviors were observed that
did not appear to be associated with reproduction. These behaviors included group swimming
"schooling" and “resting” were meagre breeders were staying at the bottom of the tank without
interacting with the rest of the breeders or participating in any evolving phenomena in the tank.
Mean duration of the phenomena was 237±37 min for "resting" and 125±11 min for
"schooling". The present work presents for the first time the behavior of meagre spawners after
spawning induction using GnRHa. The behavior of the spawners is distinguished by both samesex and different-sex phenomena. The contribution of male spawners to fertilization appeared
to be influenced both by the size of the breeders and by the signs of dominance through the
attacks they induced.
|
Language |
Greek |
Subject |
Parental contribution |
|
Spawning kinetics |
|
Αναπαραγωγή |
|
Γονική συνεισφορά |
|
Συμπεριφορά γεννητόρων |
Issue date |
2023-03-24 |
Collection
|
School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses
|
|
Type of Work--Post-graduate theses
|
Permanent Link |
https://elocus.lib.uoc.gr//dlib/8/4/4/metadata-dlib-1678434426-461957-6387.tkl
|
Views |
456 |
Digital Documents
|
|
No permission to view document.
It won't be available until: 2025-03-31
|