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Each spawning-age female can release up to 15,000 eggs at once. Snakeheads can mate as often as five times a year. This means in just two years, a single female can release up to 150,000 eggs." [7] "Since 2002, it has been illegal to possess a live snakehead in many U.S. states, where they are considered a destructive invasive species."
Male seahorses have a specialized ventral brood pouch to carry the embryos, male sea dragons attach the eggs to their tails, and male pipefish may do either, depending on their species. [4] The most fundamental difference between the different lineages of the family Syngnathidae is the location of male brood pouch. [ 5 ]
Phenotypic differences between sexes are evident even in cultured cells from tissues. [132] For example, female muscle-derived stem cells have a better muscle regeneration efficiency than male ones. [133] There are reports of several metabolic differences between male and female cells [134] and they also respond to stress differently. [135]
The first all-female (unisexual) reproduction in vertebrates was described in the fish Poecilia formosa in 1932. [51] Since then at least 50 species of unisexual vertebrate have been described, including at least 20 fish, 25 lizards, a single snake species, frogs, and salamanders. [50]
The male seahorse is equipped with a brood pouch on the ventral, or front-facing, side of the tail. When mating, the female seahorse deposits up to 1,500 eggs in the male's pouch. The male carries the eggs for 9 to 45 days until the seahorses emerge fully developed, but very small. The young are then released into the water, and the male often ...
The ZW sex-determination system is a chromosomal system that determines the sex of offspring in birds, some fish and crustaceans such as the giant river prawn, some insects (including butterflies and moths), the schistosome family of flatworms, and some reptiles, e.g. majority of snakes, lacertid lizards and monitors, including Komodo dragons.
Courtship between male and female pipefish involves lengthy and complicated shows of display. For example, in Syngnathus typhle, copulation is always preceded by a ritualized dance by both sexes. The dance involves very conspicuous wriggling and shaking motions, especially in comparison to the species' otherwise extremely secretive lifestyle.
The males do not have to compete with other males, and female anemone fish are typically larger. When a female dies a juvenile (male) anemone fish moves in, and "the resident male then turns into a female and reproductive advantages of the large female–small male combination continue". [22] In other fishes sex changes are reversible. For ...