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8/7/2019 breding behavior of fishes.
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Breeding Behavior of FishesBreeding Behavior of Fishes
Fish breeding behaviors having two broad categories.
1. Oviparous Fishes. (Egg layers)
2. Ovoviviparous / viviparous (live bearers)
Oviparous Fishes. (Egg layers) External fertilization.
classify into 3- type.
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A. Fishes that lay egg and the egg are allowed to hatch
unattended.4- sub class.
i. Egg scatterers
a. Adhesive egg (eg. Gold fish)
b. Non adhesive egg (eg. Zebra Danio)
ii. Egg hangersEgg are attached to the objects by a fine sticky thread.
(eg. Red lyre tail)
iii. Egg buryers
Bury the egg in soil before advent of summer season.
( eg. Blue gularis)iv. Egg stowers
lay egg inside the freshwater mussel
(eg. Bitterling )
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B. Fishes lay egg & egg are guarded by either male or female
/ both ,but not contact with body of parents.
classify into 5 type
i. Egg Anchorers.
spawning site like (surface of stones or wooden piece
etc) Eg; Angle fish
ii. Egg Splashers.
egg lay on overhanging leaf or stone
Eg; Splashing tetra
iii. Egg Scoopersegg laying and scoops out a depression by swimming in a
circle.
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iv. Egg Hider
the prefer to hide their eggs out of sight.
v. Nest builder
prepare the nest for keeping the egg safely fill
hatching.
Eg; siamese fighting fish.
C. Fishers lay egg & egg are guarded by parent (direct
contact, or egg carriers)
Mouth Breeder ;- Male catch the egg in mouth .
Eg; Betta , Tilapia.
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2. Ovoviviparous / viviparous They produced young ones. (live Bearer)
Internal fertilization.
Egg are fertilized in the female body and emerge fully
formed young.
Eg. Swart tail , Molly.
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Neuroendocrine Regulation InNeuroendocrine Regulation In
Fishes.Fishes. Neuroendocrine Regulation of reproduction in teleost
fishes.
Environmental factor like temp, light, pheromones,photoperiod, other factor are vital role in fish
reproduction. temp, light, pheromones, photoperiod, and other
factor are received by sensory receptors centralnervous system (CNS)
CNS control & secretion of GnRH (Gonadotropin
Releasing Hormones)
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GnRH in turn stimulates the gonadotroph cell of pituitary
to produce gonadotrophs. Two gonadotropins like GtH-I, GtH-II.
They are secreted during vitellogenic phase of oocyte
development, & postvitellogenic phase.
GtH-I induces the secretion of estradiol from folliclecells.
Both thecal cell and granulosa cells have receptors for
GtH-I.
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GtH-I stimulates the thecal cell to produce testeosterone
from the cholesterol precursor. The synthesis of 17 OH progesterone
androstenedlone testosterone, these enzymes are
controlled by GtH-I molecule
Binding of GtH-I to the receptor of granulosa cell inducesthe conversion of testosterone to estradiol.
Estradiol liberated into blood circulation and act on liver
cell to produce vitellogenin,(yolk protein).
Vitellogenin is carried to oocyte.
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Vitellogenin is transformed into yolk protein lipovitellin,
phosvitin and deposited as yolk granules.
GtH-I also cause the differentiation and development of
follicular envelopes.
GtH-II secreted from gonadotrophs of PG
GtH-II is stimulate from gonadotrophs of oocyte to producea hormone called MIH (Maturation Inducing Hormone) from
17 OH progesterone.
MIH stimulates the production of MPF (Maturation
Promoting Factor) in the cytoplasm of oocyte.
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Vitellogenin is transformed into yolk protein lipovitellin,
phosvitin and deposited as yolk granules.
GtH-I also cause the differentiation and development of
follicular envelopes.
GtH-II secreted from gonadotrophs of PG
GtH-II is stimulate from gonadotrophs of oocyte to producea hormone called MIH (Maturation Inducing Hormone) from
17 OH progesterone.
MIH stimulates the production of MPF (Maturation
Promoting Factor) in the cytoplasm of oocyte.
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Environmental stimulii
Light Temp. Pheromones
Photoperiod
Central Nervous
System
Hypothalamus
(Brain)
Hypophysis
(Pituitary))
GnRH
GtH-I GtH-II
Ovary
(gonads)
Vitellogenicooc te
Post vitellogenicoocyte
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Oocyte
Envelopes
17,- Estradiol
Liver
Vitellogenin Ooplasm
Vitellogenesis
Gravidoocyte
Oocyte
Envelopes
MIH
Ooplasm
MPF
Germinal vesicle
1st mat Division
Mature oocyte
Ovulation ovum
sperm
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Thank youThank you
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