Fish reproductive organs include paired testes and ovaries located in the abdominal cavity. Reproduction can involve unisexuality, bisexuality, or hermaphroditism. The testes produce sperm and hormones, while ovaries contain developing oocytes at different stages of maturation. Environmental and nutritional factors influence reproduction. Understanding fish reproductive physiology is important for aquaculture practices like controlled spawning and seed quality improvement.

1. Reproductive Physiology
and Morphology in Fish
Presented By
Basant singh
M.F.Sc Previous year, 2020-21
College of Fisheries, Kawardha

2. Introduction
•Fish reproductive organs includes testes and ovaries.
•In most fishes gonads are paired organs of similar
size.
•Wide variety of patterns of reproduction such as
unisexuality,bisexuality and hermaphroditism.

3. SEXUALITY IN FISH
Unisexual
Eg. Poecilidae
Bisexual Hermaphroditism
Asynchronous
Synchronous
Eg. Serranus
scriba, S.
cabrilla
Differentiated
gonochoristic
Eg. Platy fish,
Common carp,
Gold fish
Undifferentiated
gonochoristic
Eg. Eel, Salmon
Protandrous
Eg. Sea bass
Protogynous
Eg. Epinephalus

4. Importance of reproductive physiological
To develop maturation under captive condition.
To enhance sperm count and viability.
Control of excess and undesirable spawning.
Seasonality of spawning.
The seed quality improvement.

5. Facter affecting reproduction
Environmental factors- Light , temperature & water
quality parameter.
Intrinsic physiological factor- Hormonal,
Neurohormonal
Nutritional requirement of fish- natural food, feeding
pattern, balanced diet required for optimum gonadal
growth.

6. Male Reproductive System
 In male fish, the reproductive organs consists of a pair of
testes situated on either side ventral to the kidneys in the
abdominal cavity.
 The testis has to major function ,The production of
spermatozoa (Spermatogenesis) and another fuction is the
production of steroids (sterodogenesis).
 The testis may be elongeted, sac- like or lobelated,may be
rounded or triangular in crosssection

7. Cont.….
In some fishes, the anterior 3/4 part of each testis is
functional and rest posterior part is sterile is Mystus
seenghala and Tor tor.
The posterior sterile portion contains empty lamellae,
probably for the storage of the sperms during
breeding season.
The two oviducts joinand open to the exterior by a
separate genital aperture, or by a common urino-
genital opening

8. Urinogenital organs of Male fish

9. Female Reproductive System
The reproductive organs of the female fish: A Pair of
ovaries, which are present in the abdominal cavity
ventral to the kidneys.
Fish ovaries may be three types – Gymnovarian ,
secoundry Gymnovarian , Cystovarian .
 Gymnovarian- the oocytes are released directly into
the coelomic cavity and then enter the ostium.

10. Cont………
 Secondary Gymnovarian- ovaries release ova into the coelam
from go directly into the oviduct.
 Cystovarian- characterize most teleosts ,in this types of ovary
,the mature oocytes are released by pore to the outside.

11. The ovaries are elongated sac –
like structure.
The two ovaries may be of equal
or unequal size and is continued
posteriorly into a short oviduct.
The two oviduct join and open to
the exterior by a separate genital
aperture, or by a common urino-
genital opening .

12. Urinogenital organ of Cirrhinus (female)

13. The wall of ovary is composed of
Three layers
(1)An outermost thin peritoneum.
(2)A tunica albuginea made up of connective tissue, muscle fibres and
blood capillaries
(3)The innermost layer called germinal epithelium, which projects into
the ovocole in the form of lamellae.
(4)The ovarian wall is thick during immature or non-breeding season ,
but is thin and highly vascular during spawning period.
(5)The ovigerous lamellae that project into the ovocoel are the seat
for the maturation of oocytes.

14. • which can be seen in various stages of
Development in the section of the ovary.
• The germ cell or the oogonia originate from the
germinal epithelium, and can be seen in small groups
or nests in the lamellae.
• An oogonium has a nucleus surrounded by a of
chromophobic ooplasm, and undergoes through a
number of stage before giving rise to a ripe ovum.
.

15. • During maturation an oogonium increases in size, due
to the accumulation of ooplasm , and several
cytological change also take place .
• A developing egg is called an oocyte, and its several
stage can be seen in a section of the ovary various stage
of the oocyte.

16. Immature ovary of fish

17. Overy of Fish Mature

18. Oocyte 1: This is the youngest oocyte , slightly larger
than the oogonium .
It is spherical having a nucleus with 2or 3 nucleus and
basophilic cytoplasm .
OocyteII: There is increase in the size oocyte and several
small nucleoli are seen along the periphery of the nuclear
membrane.
A yolk nucleus may be seem lying close to the nuclear
membrane is some oocytes .
Later , the yolk nucleus migrates towards the periphery
of the oocyte.

19. OocyteIII; There is further increase in the size of the
oocyte .thin layer of follicular cells appears around the
cytoplasm . A few nucleoli can be seen in the cytoplasm
of the oocyte ,and appear to have passed out of the
nuclear membrane.
Oocyte IV: The oocyte further increases in size and can
be distinguished by the presence of an number of small
, clear vacuoles called the yolk vesicles along the
periphery of the ooplasm . In the early stage , the yolk
vesicles appear to be empty and do not take stain . In
many oocyte of this stage

20. Oocyte V: The oocyte further grows in size and there is
increase in the number of yolk vesicles , where may fill
the entire ooplasm. Avitelline memberan consisting of
zone radiata is seen between the ooplasm and the
follicular layer.
Oocyte VI: Minute yolk granules appear in the
ooplasm and accumulate in the peripheral regione .
Gradually , the yolk granules appere in the whole
ooplasm and the smaller ones fuse to form large size
yolk globules.

21. Oocyte VII: The yolk vesicles fuse and become large ;
yolk globules increase in size due to deposition of more
yolk . Some yolk vesicles are pushed toward the periphery
to the form of layer of cortical alveoli. The nucleus now
moves toward the periphery.
Stage in the maturation of an oocyte