Spawning
Spawning is the release of eggs and sperm by aquatic animals for reproduction, usually into water where fertilization can occur.
External fertilization: Fertilization in which eggs and sperm unite outside the bodies of the parents. Many spawners release gametes into water, where fertilization occurs externally.
Fish hatchery: A facility that breeds and raises fish, often for aquaculture or release into the wild. Hatcheries induce or collect spawning to produce eggs and young fish.
Coral spawning: The release of eggs and sperm by corals, often in synchronized mass events. Corals demonstrate highly timed spawning in which many colonies release gametes together.
Fish migration: The regular movement of fish between habitats, often for feeding, growth, or reproduction. Many species migrate specifically to reach suitable spawning sites.
Gamete: A reproductive cell, such as an egg or sperm, that joins another gamete during fertilization. Spawning releases the eggs and sperm that serve as gametes.
Spawning stock biomass: The total mass of mature fish in a population capable of reproducing. Fisheries use it to estimate how much reproductive capacity remains in a stock.
Pacific salmon: Salmon species native to the Pacific basin that migrate between ocean and freshwater habitats. Adults return to freshwater spawning grounds, often completing a long migration.
Anadromy: A life-history pattern in which fish grow at sea and migrate into freshwater to reproduce. Salmon exemplify this migration between marine feeding grounds and freshwater spawning habitat.
Sperm competition: Competition among sperm from different males to fertilize the same eggs. When several males spawn near one clutch, their sperm compete for fertilization.
Fishery closure: A restriction that temporarily or permanently prohibits fishing in a defined area or period. Seasonal closures can reduce harvest while fish gather to spawn.