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千万别提那条母的，请看
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Murray cod reach sexual maturity at 4 to 6 years of age (most fish 5 years) and 2 to 3 kg in weight. The species has relatively low fecundity (fertility) compared to many other freshwater fish. Egg counts range from <10,000 eggs for a barely mature female to approximately 90,000 for females around the 22 kg mark. It is likely that large female Murray cod that are in the 15-25 kg range and "in their prime" are perhaps the most important breeders because they produce the most eggs and for other reasons; research is now showing large females in most fish species are also important because they produce larger larvae with larger yolk sacs and are also more experienced breeders that display optimal breeding behaviours (e.g. Trippel, 1995; Marteinsdottir & Steinarsson, 1998; Marteinsdottir & Begg, 2002). Both of these factors mean the spawnings of large female fish have far higher larval survival rates and make far greater reproductive contributions than the spawnings of small female fish. Such large females may also have valuable, successful genes to pass on.
[ 本帖最后由 melwen2009 于 2012-1-12 22:33 编辑 ] |
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楼主:hueypso
发表于 2012-1-6 09:35
