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Fish reproduction. A pair of bettas spawning under a bubble nest. Fish reproductive organs include testes and ovaries. In most species, gonads are paired organs of similar size, which can be partially or totally fused. [1] There may also be a range of secondary organs that increase reproductive fitness.
Five modes of reproduction can be differentiated in fish based on relations between the zygote(s) and parents: [6] [7] Ovuliparity: Fertilization of eggs is external; zygotes develop externally. Oviparity: Fertilization of eggs is internal; zygotes develop externally as eggs with large vitellus.
However, most fish and other spawning animals are iteroparous. When the internal ovaries or egg masses of fish and certain marine animals are ripe for spawning they are called roe. Roe from certain species, such as shrimp, scallop, crab and sea urchins, are sought as human delicacies in many parts of the world.
Internal fertilization is the union of an egg and sperm cell during sexual reproduction inside the female body. Internal fertilization, unlike its counterpart, external fertilization, brings more control to the female with reproduction. [1] For internal fertilization to happen there needs to be a method for the male to introduce the sperm into ...
Teleost. Teleostei (/ ˌtɛliˈɒstiaɪ /; Greek teleios "complete" + osteon "bone"), members of which are known as teleosts (/ ˈtɛliɒsts, ˈtiːli -/), [ 4 ] is, by far, the largest infraclass in the class Actinopterygii, the ray-finned fishes, [ a ] and contains 96% of all extant species of fish. Teleosts are arranged into about 40 orders ...
Fish anatomy. Fish anatomy is the study of the form or morphology of fish. It can be contrasted with fish physiology, which is the study of how the component parts of fish function together in the living fish. [1] In practice, fish anatomy and fish physiology complement each other, the former dealing with the structure of a fish, its organs or ...
Fish embryos go through a process called mid-blastula transition which is observed around the tenth cell division in some fish species. Once zygotic gene transcription starts, slow cell division begins and cell movements are observable. [4] During this time three cell populations become distinguished. The first population is the yolk syncytial ...
This type of reproduction had been seen before in bony fish, but not in cartilaginous fish such as sharks. [71] In the same year, a female Atlantic blacktip shark in Virginia reproduced via parthenogenesis. [72] On 10 October 2008, scientists confirmed the second case of a "virgin birth" in a shark.