page_title: Spawn (biology)
section_title: Guarders
hierarchical_section_title: Spawn (biology) / Spawning strategies / Guarders
caption_attribution_description: The stickleback and its nest
context_page_description: Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, to spawn refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquatic mammals and reptiles, reproduce through the process of spawning.
  Spawn consists of the reproductive cells of many aquatic animals, some of which will become fertilized and produce offspring. The process of spawning typically involves females releasing ova into the water, often in large quantities, while males simultaneously or sequentially release spermatozoa to fertilize the eggs.
  Most fish reproduce by spawning, as do most other aquatic animals, including crustaceans such as crabs and shrimps, molluscs such as oysters and squid, echinoderms such as sea urchins and sea cucumbers, amphibians such as frogs and newts, aquatic insects such as mayflies and mosquitoes and corals, which are actually small aquatic animals—not plants. Fungi, such as mushrooms, are also said to "spawn" a white, fibrous matter that forms the matrix from which they grow.
context_section_description: Guarders protect their eggs and offspring after spawning by practicing parental care (also called brood care). Parental care is an "investment by parents in offspring that increases the offspring's chances of surviving (and hence reproducing). In fish, parental care can take a variety of forms including guarding, nest building, fanning, splashing, removal of dead eggs, retrieval of straying fry, external egg carrying, egg burying, moving eggs or young, ectodermal feeding, oral brooding, internal gestation, brood-pouch egg carrying, etc."
  Territorial behaviour is generally necessary for guarders, and the embryos are almost always guarded by males (apart from cichlids). There is a need to be territorial because looking after embryos usually includes defending the site where they are being looked after. It also often means there is competition for the best egg-laying sites. Elaborate courtship behaviour is usual among guarders.
  Guarding males keep the embryos safe from predators, keep oxygen levels high by fanning water currents, and keep the area free from dead embryos and debris. They protect the embryos until they hatch, and often look after the larval stages as well. The time spent guarding can range from a few days to several months.
caption: The stickleback glues plant material to make its nest
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