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Exposure of zebra fish to a chemical environmental agent, analogous to that caused by anthropogenic pollution, amplified the effects of inbreeding on key reproductive traits. [40] Embryo viability was significantly reduced in inbred exposed fish and there was a tendency for inbred males to sire fewer offspring.
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 .
Fish anatomy is the study of the form or morphology of fish. It can be contrasted with fish physiology, ... Fish reproductive organs include testicles and ovaries.
The spawn (eggs) of a clownfish.The black spots are the developing eyes. Spawn is the eggs and sperm released or deposited into water by aquatic animals.As a verb, to spawn refers to the process of freely releasing eggs and sperm into a body of water (fresh or marine); the physical act is known as spawning.
Nuptial tubercles occasionally develop on female fish also, but this is rare, and they are often barely visible to the naked eye. [ 6 ] Nuptial tubercles have been described as an honest signal of the general health of the male bearer, in common with other biological ornaments . [ 7 ]
Fish were observed floating inverted completely motionless with the illicium hanging down stiffly in a slight arch in front of the fish. The illicium was hanging over small visible burrows. It was suggested this is an effort to entice prey and an example of low-energy opportunistic foraging and predation.
Chimaera reproduction resembles that of sharks in some ways: males employ claspers for internal fertilization of females and females lay eggs within spindle-shaped, leathery egg cases. [1] Unlike sharks, male chimaeras have retractable sexual appendages (known as tentacula) to assist mating.
Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin which serve to channel semen into the female's cloaca during mating. The act of mating in some fish including sharks usually includes one of the claspers raised to allow water into the siphon through a specific orifice. The clasper is then inserted into ...