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Fish Reproduction - Anatomy & Physiology (view source)
Revision as of 12:45, 29 July 2008
, 12:45, 29 July 2008→Oviparity
== Oviparity ==
== Oviparity ==
* 97% of fish
* Mostly external fertilisation, with the male and female fish shedding their gametes into the surrounding water.
* A few oviparous fishes practise internal fertilisation, with the male using an intromittent organ to deliver sperm into the genital opening of the female.
** Species that pracitce internal fertilization include oviparous sharks, such as the horn shark, and oviparous rays, such as skates.
** In these cases, the male is equipped with a pair of modified pelvic fins known as claspers.
* The newly-hatched young are called larvae.
** Usually not well developed, carry a large yolk sac (from which they gain their nutrition) and are very different in appearance to juvenile and adult specimens of their species.
** The larval period in oviparous fish is relatively short, usually several weeks.
** Larvae rapidly grow and change appearance and structure (metamorphosis) to resemble juveniles of their species.
*** During this transition larvae use up their yolk sac and must switch from yolk sac nutrition to feeding on zooplankton prey.
== Ovoviviparity ==
== Ovoviviparity ==