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In competitions between sperm from an unrelated male and from a full sibling male, a significant bias in paternity towards the unrelated male was observed. [4] It is a theory that females avoid inbreeding more than males due to the fact that when they mate with a sibling, they obtain 50% less sperm in their ovarian cavities in comparison to ...
Horses can breed with Przewalski's horse to produce fertile hybrids. Mule, a cross of female horse and a male donkey. Hinny, a cross between a female donkey and a male horse. Mules and hinnies are examples of reciprocal hybrids. Kunga, a cross between a donkey and a Syrian wild ass. Zebroids. Zeedonk or zonkey, a zebra/donkey cross. Zorse, a ...
A spawning bed is an underwater solid surface on which fish spawn to reproduce themselves. In fishery management , a spawning bed is an artificial bed constructed by wildlife professionals in order to improve the ability of desired game fish to reproduce.
Hormonal treatments can advance spawning by two to three weeks. [5] Manipulating photoperiod can alter spawning time by over four months and is cheap and straightforward to achieve. [5] Broodstock managers can use or select for traits such as fast growth rates or disease resistance over generations to produce more desirable fish. [15]
Removal of piscivorous fish can change lake water from clear to green by allowing phytoplankton to flourish. [24] In the Eel River, in Northern California, fish (steelhead and roach) consume fish larvae and predatory insects. These smaller predators prey on midge larvae, which feed on algae. Removal of the larger fish increases the abundance of ...
The direct selection for biological traits through fishery practices is the result of fishery management regulations, and gear restrictions and selectivities. [1] The most obvious artificial selection for traits through management legislation can be observed in the imposed regulations on size (minimum landing size), sex, seasonality, and locations.
To produce one kilograms of farmed salmon, products from several kilograms of wild fish are fed to them – this can be described as the "fish-in-fish-out" (FIFO) ratio. In 1995, salmon had a FIFO ratio of 7.5 (meaning 7.5 kilograms of wild fish feed were required to produce one kilogram of salmon); by 2006 the ratio had fallen to 4.9. [ 103 ]
The concept is in contrast to inbreeding depression, although the two effects can occur simultaneously on different traits. [2] Outbreeding depression is a risk that sometimes limits the potential for genetic rescue or augmentations. [ 1 ]