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Tilapia, Environmental risks and Genetic alternatives

Tilapia, Environmental risks and Genetic alternatives. I. Hashemzadeh Yazd August 2014. Native: Africa and M. East Over 3000 years background Cichlids : Oreochromis, Sarotherodon and Tilapia . All important tilapia outside of Africa are Oreochromis ,

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Tilapia, Environmental risks and Genetic alternatives

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  1. Tilapia, Environmental risks and Genetic alternatives I. Hashemzadeh Yazd August 2014

  2. Native: Africa and M. East • Over 3000 years background • Cichlids : Oreochromis, Sarotherodon and Tilapia. • All important tilapia outside of Africa are Oreochromis, • More than 90 percent of farmed tilapia outside Africa are Nile tilapia

  3. Best growth- above 250C • Spawning - above 200C • Death- 10 to 120C It can seek for warmer parts • Up to 15 ppt : growth and spawning • Tolerate varied Env. conditions

  4. Nile Tilapia Blue Tilapia O. aureus Red Tilapia Mozambique Tilapia O. mossambicus

  5. Tilapia nilotica, Sarotherodon niloticus, and Oreochromis niloticus

  6. Interrupted lateral line • laterally compressed and deep-bodied • long dorsal fins • The forward portion of the dorsal fin is heavily spined • Spines are also found in the pelvis and anal fins • usually wide vertical bars down the sides of fry, fingerlings, and sometimes adults

  7. O. niloticus

  8. phytoplankton zooplankton

  9. Tilapia can be cultured in fresh and salt water. 1. All tilapia can be grown in fresh water. 2. Mossambique tilapia and red tilapia with Mossambique tilapia genes can be grown in salt water.

  10. and defend the fry Females incubate eggs Reproduction Males dig and defend a nest

  11. All tilapia species are nest builders • Sarotherodon and Oreochromis are mouth brooders • In Oreochromis: only females, in Sarotherodon either the male or both male and female

  12. 1. ponds 2. cages ( hapas ) 3. tanks Tilapia can be spawned in:

  13. Fry can be harvested: 1. 18 days after stocking brood fish 2.40 days after stocking brood fish

  14. 1. partial harvested 2.completely harvested Fry can be:

  15. Eggs can be removed from females: Incubating tilapia eggs Yolk-sac tilapia fry

  16. Tilapia can be cultured as: 1. Mixed sexes - males and females together 2. Mono-sex - only males

  17. Grow-out: Mixed-sex Culture Advantages: 1. Technically easy Disadvantages: 1. Small harvest weight 2. Mixed sizes at harvest

  18. Mono-sex culture Advantages: 1. Large harvest weight 2. Uniform size at harvest Disadvantages: 1. Technically difficult

  19. Stocking a predacious fish with mixed-sex tilapia will control tilapia density and increase final harvest weight. Largemouth bass in the U. S. A.

  20. Mono-sex male tilapia populations can be produced by: 1. Visual selection 2. Hybridization 3. Sex-reversal 4. Genetic manipulation Male Populations

  21. Visual Selection of the Genital Papilla

  22. Hybridization Male Hornorum tilapia ZZ XZ XX Female Nile tilapia All-male hybrid tilapia

  23. اهميت جمعيت هاي تك جنس يا عقيم؟ • دوشكلي جنسي (ماهيان خوراكي و تزئيني): تيلاپيا؟ قزل آلا؟ • بلوغ زودرس در يك جنس يا تكثير ناخواسته • تفاوت جنسي در مقاومت به شرايط محيطي • ممنوعيت ورود گونه هاي غيربومي، موجودات تراريخته و ملاحظات زيست-محيطي (صيد تفريحي، كنترل بيولوژيك و گونه هاي اهلي)

  24. راه كار؟ • جلوگيري از توليد مثل در طبيعت! روش ها: • روش هاي دستي • عقيم سازي • دورگ گيري • ماده زايي • نرزايي • پلي پلوئيدي • تغيير جنسيت • تغيير جنسيت و تكثير

  25. روش دستي • چشمي و رقم بندي معايب پرزحمت و پرخطا اتلاف سرمايه!

  26. عقيم سازي شيميايي و مكانيكي • جراحي: نياز به نيروي انساني و امكان تلف شدن ماهي، غير دائم • مواد شيميايي: اختلال در چرخه توليد گنادوتروپين ها: متال ليبور و استات سيپروترون، استات ترن بلون: قابل بازگشت • پرتو تابي: اشعه ايكس و گاما: قابل بازگشت • مشكلات: امنيت غذايي و كارايي كم

  27. تغيير جنسيت به روش هورموني • جنسيت ژنتيكي و جنسيت فنوتيپي؟ • زمان تمايز در تيلاپيا 3-4 هفته پس از تفريخ • تعيين جنسيت بيشتر به اندازه وابسته است تا به سن • تيمارهاي استروژني و اندروژني • اندروژن: 17α- methyl testosterone، 19-norethynyl testosterone، 11-ketotestosterone • استروژن ها: 17β- oestradiol

  28. روش اعمال • حمام، غذا، و كاشت • معايب: تغيير جنسيت ناقص و كارايي كم • عوامل مؤثر: گونه ماهي، ژنتيك، نوع هورمون، مقدار هورمون، طول مدت تيمارداري و زمان آن • لازم است فرايند تغيير جنسيت در محيط مراكز تكثير و در آب عاري از پلانكتون انجام شود • زمان مهم براي تيمارداري: از زمان رسيدن ماهي به طول 12 ميليمتر به مدت 28 روز

  29. MITOTIC GYNOGENESIS

  30. MITOTIC ANDROGENESIS

  31. Genetic Manipulation 1) XXF + XYM estrogen XXF + XY”F” 2) XY”F” x XYM XXF + 2 XYM + YYM 3) XXFx YYM 100% XYM

  32. عوامل مؤثر بر تعيين جنسيت • ژنتيك • محيط

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