breding behavior of fishes

8/7/2019 breding behavior of fishes.

1/14

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.


2/14

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 )


3/14

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.


4/14

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.


5/14

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.


6/14

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)


7/14

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.


8/14

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.


9/14

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.


10/14

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.


11/14

Environmental stimulii

Light Temp. Pheromones

Photoperiod

Central Nervous

System

Hypothalamus

(Brain)

Hypophysis

(Pituitary))

GnRH

GtH-I GtH-II

Ovary

(gonads)

Vitellogenicooc te

Post vitellogenicoocyte


12/14

Oocyte

Envelopes

17,- Estradiol

Liver

Vitellogenin Ooplasm

Vitellogenesis

Gravidoocyte

Oocyte

Envelopes

MIH

Ooplasm

MPF

Germinal vesicle

1st mat Division

Mature oocyte

Ovulation ovum

sperm


13/14

Thank youThank you


14/14

Documents

breding behavior of fishes