Nile tilapia Oreochromis niloticus
تعريف
Nile tilapia is an African cichlid of the Nile basin, the coastal rivers of Israel and the Senegal, Gambia, Volta and Niger systems, now farmed across the tropics; FAO FishStat records 5,612,925 tonnes in 2024. It is a maternal mouthbrooder that reaches sexual maturity in three to six months depending on temperature, and precocious breeding inside grow-out ponds causes overcrowding and stunting. That single reproductive fact shapes the industry: commercial culture runs all-male populations, classically produced by feeding 60 mg of methyltestosterone per kilogram of feed to newly hatched fry for three to four weeks. Conditions are warm and forgiving, with 25 to 32 degrees C preferred, dissolved oxygen above 3 mg/l, salinity tolerated to 28 ppt and six to twelve months from egg to market fish; cold is the hard limit, feeding stopping below about 16 degrees C and death following near 13 degrees C. Streptococcus agalactiae is the signature bacterial disease, breaking out above 26 degrees C at high stocking density with exophthalmia, corneal opacity and spiralling swimming, mortality that has passed 95 per cent, and recognised zoonotic potential. Tilapia lake virus has killed up to 90 per cent of stock in outbreaks and poses no public health concern.
المؤشّرات الحيوية
- الوزن عند البلوغ
- ≤ 4.3
- أقصى طول
- 60
- العمر عند أول تكاثر
- 3 – 6 months
- حرارة الماء المثلى
- 28 – 32 C
- العمر المتوقّع
- ≤ 9 years
maximum published weight; market fish are harvested far smaller, and the sources fetched give 6-12 months from egg to food size rather than a harvest weight
maximum length, standard length, male/unsexed
FishBase: sexual maturity at 3-6 months depending on temperature; UF/IFAS reports hybrid tilapia spawning precociously at 2-3 months and 8-10 cm
GROW-OUT optimum ('Optimum growth'), explicitly stated by UF/IFAS. TAXON CAVEAT, which must travel with this value: the publication is 'Culture of Hybrid Tilapia: A Reference Profile' and its figures are for cultured hybrid tilapia (predominantly O. aureus crossed with O. niloticus, O. mossambicus and O. hornorum), not for Oreochromis niloticus specifically; the author states the figures are guidelines. No O. niloticus-specific grow-out optimum was found: FAO's own cultured species fact sheet for O. niloticus gives only lethal limits (11-12 C and 42 C) and a PREFERRED temperature of 31-36 C, which is a thermal-preference descriptor, not a culture optimum. The withdrawn 25-32 came from the same UF/IFAS page but is its 'preferred for raising hybrid tilapia in intensive culture' sentence, not its stated optimum.
MAXIMUM RECORDED AGE in the wild, not a typical or productive life. AnAge sample size Medium, data quality Acceptable; this is the same 9-year figure FishBase carries. It does not settle the conflict with UF/IFAS, which reports fish of eleven to twelve years - that disagreement still has to be disclosed on the profile. Store 9 as the curated maximum, not as a hard ceiling.
تُعرض المؤشّرات المُوثَّقة فقط. غياب مؤشّر هنا يعني أنه غير مذكور في مرجع موثوق لهذا النوع — لا أنه ناقص من الصفحة.
السلالات — لا يوجد ارتباط
لا سلالة منشورة لهذا النوع بعد. السلالات محصودة بأعداد كبيرة وتنتظر اعتماداً بشرياً قبل أن تُنشر.
كل السلالات ←العلامات السريرية — لا يوجد ارتباط
لا علامة سريرية منشورة بعد — وهي أيضاً ما ينقص باحث العلامات.
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