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Reproduction
Fish Reproduction Strategies
The full spectrum of fish breeding - from broadcast spawning of millions of eggs to internal fertilization and live birth.
System: Reproductive Level: Intermediate Discipline: Physiology
📖 Overview
Fish exhibit greater reproductive diversity than any other vertebrate group. Oviparous species release eggs to be fertilized externally (most bony fish). Ovoviviparous species retain eggs internally until hatching (many sharks, guppies). Viviparous species nourish young via a placenta-like structure (hammerheads, some rockfish). Some fish are hermaphroditic; some reproduce parthenogenetically; some are protandrous or protogynous.
🔑 Key Concepts
Broadcast spawning, nest building, mouthbrooding, ovoviviparity, viviparity, hermaphroditism, parthenogenesis.
🐟 Examples
Ocean sunfish (Mola mola) release up to 300 million eggs per spawn - the highest of any vertebrate. Great white sharks give birth to just 2-10 fully-formed pups after 11 months gestation.
✨ Fun Fact
Amazon molly (Poecilia formosa) is an all-female species that reproduces via gynogenesis - eggs must be triggered by sperm from a related species, but the sperm contributes no DNA.