fish reproduction types

1. Reproduction of Fish
Live-Bearing
Top: Salmon (Oviparous)
Bottom: Tilapia (Mouth-Brooding)
Egg-Laying
 Ovoviviparous
o Eggs hatch within the mother
o First Type: The embryo develops
in the egg while the egg is still
within its follicular covering
within the ovary, and ovulation
(or release of the egg) and birth
occur at the same time
o Second Type: The eggs are
released from the protective
follicles into the cavity of the
hollow ovary, where
development continues
 Viviparous
o Unborn young receive
nourishment from mothers
tissues
o Primary Way: The walls of the egg
follicle are in intimate contact
with the embryo, supplying it
with nourishment
 Oviparous
o Simplest form: Females will scatter their
eggs in a water column and males will
eject their “Milt” at the same time
o Some species of fish take greater care in
egg laying locations however and will
return to their place of birth to lay their
eggs
o Certain species have adapted their eggs
to have a sticky outer coating so that
they adhere to rocks instead of free
floating in the water column
 Mouth-Brooding
o A large number of fish species incubate
fertilized eggs in their mouths or gills
until they hatch. Then the frys will
continue to use their parents mouth or
gills until they are grown.
In captivity fish farmers are able to raise both types through the use of carefully monitored hatcheries, for Egg-Laying species, and monitoring critical water
statistics such as oxygen, acidity, ammonia, and heavy metal levels, for Live-Bearding species.
Nurse Shark (Ovoviviparous) Beta Fish (Oviparous) Nest Hammerhead Shark (Viviparous)