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Selective breeding (also called artificial selection) is the process by which humans use animal breeding and plant breeding to selectively develop particular phenotypic traits (characteristics) by choosing which typically animal or plant males and females will sexually reproduce and have offspring together.
The purpose of the modifications is to increase the speed at which the fish grows without affecting its ultimate size or other qualities. Fish-farmed Atlantic salmon growth rates have already been improved over wild fish as a result of traditional selective breeding practices. However, GM fish are able to grow even faster and grow to market ...
This will involve enhancing the capacity of local personnel in selective breeding, genetic improvement, statistical analysis and hatchery management through specialized training courses. Once a high performing tilapia strain (or strains) has been developed, the establishment of satellite hatcheries will increase the availability and decrease ...
When breeding kissing gouramis, soft water is preferred. As the fish do not build nests, lettuce leaves placed on the water surface serve as a spawning medium. The lettuce will eventually host bacteria and infusoria upon which the fish will feed. The maximum length for kissing gouramis in aquariums is between 30 and 40 cm (12 and 15.5 in).
However, most fish do not possess seminiferous tubules. Instead, the sperm are produced in spherical structures called sperm ampullae. These are seasonal structures, releasing their contents during the breeding season, and then being reabsorbed by the body. Before the next breeding season, new sperm ampullae begin to form and ripen.
Pit spawning, also referred to as substrate breeding, is a behavior in cichlid fish in which a fish builds a pit in the sand or ground, where a pair court and consequently spawn. [75] Many different factors go into this behavior of pit spawning, including female choice of the male and pit size, as well as the male defense of the pits once they ...
The precursor to the Bubble Eye, known as the Toadhead or hama-tou, had upturned eyes and very small, bladder-like sacs. [6] [7] Through selective breeding, the bubble eye is currently available with either a long or more rounded body and the choice between matte, metallic or nacreous scales. [8]
The breeding and marketing of fancy goldfish with extreme mutations is sometimes seen as cruel practice by fish keepers and animal rights activists. Because the Pearlscale Goldfish has been bred to such a spherical shape, it may experience problems with its spine and internal organs, reducing its quality of life and longevity. [5]