Behavior
B
Broadcast Spawning
Quick Definition
A reproductive strategy in which fish release eggs and sperm simultaneously into the open water, leaving fertilisation and offspring development to chance.
📖 Full Definition
Broadcast spawning (or pelagic spawning) is the release of large numbers of eggs (oocytes) and sperm into the water column, where fertilisation occurs externally. It is the most common reproductive strategy in marine fish. Success depends on synchronised spawning aggregations, appropriate environmental conditions (temperature, salinity, currents that carry larvae to suitable nursery habitat). Individual fecundity is high to compensate for the enormous mortality of larvae before settlement. Large cod may release 1–9 million eggs per spawning event.
💡 Examples & Context
Coral reef fish (parrotfish, groupers, wrasses) form spawning aggregations at predictable sites and times of year for broadcast spawning.