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| == Oviparity == | | == Oviparity == |
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| + | * 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. |
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| == Ovoviviparity == | | == Ovoviviparity == |