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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.
Polyandry in fishes is a mating system where females mate with multiple males within one mating season. [1] This type of mating exists in a variety of animal species. [1] Polyandry has been found in both oviparous and viviparous bony fishes and sharks. [2] General examples of polyandry occur in fish species, such as green swordtails [1] and ...
The breeding season is when seasonal breeders reproduce. Various variables can affect when it occurs. [3] A primary influence on the timing of reproduction is food availability. Organisms generally time especially stressing events of reproduction to occur in sync with increases in food availability.
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Visually similar structures to nuptial tubercles are produced by male loricariid catfishes during the mating season, in similar places to nuptial tubercles (snout and fins). These are actually hypertrophied odontodes , which are therefore dermal teeth, rather than keratin, and are covered by flesh containing taste buds.
Unlike smaller dasyurids, male die-off in D. hallucatus is not due to endocrine system changes, and there was no observed spermatogenic failure after the mating season ended. [12] If male D. hallucatus survive past their first mating season, they may be able to engage in a second mating season. While the individuals in a 2001 study mostly died ...
A grizzly bear ambushing a jumping salmon during an annual salmon run. A salmon run is an annual fish migration event where many salmonid species, which are typically hatched in fresh water and live most of their adult life downstream in the ocean, swim back against the stream to the upper reaches of rivers to spawn on the gravel beds of small creeks.
[12] [16] The breeding season is between midspring and midautumn, with the peak breeding time being around summer. Females can have up to nine broods per mating season, with the average size ranging from five to 100. [12] The variability of the average brood size is due to many variables, including temperature, age, and available nutrients.