1. Tilapia Aquaculture – An Overview: Selection of Broodstocks and Hatchery Systems Kevin Fitzsimmons University of Arizona, Professor World Aquaculture Society, Immediate Past-President American Tilapia Association, Sec./Tres. Pablo Gonzalez Alanis Universidad Autonoma de Tamaulipas, Professor World Aquaculture Society, Student Liaison Program Coordinator, Aquaculture TIES Hermosillo, Son. Mexico Dec. 2, 2005

2. Tilapia breeds F Proper selection of fish for your type of production system is second most important decision (after marketing) F There are several species, hybrid strains, and breeding programs available F Goals are fast growth, good FCR and mostly male fish F Must determine if farm will buy fry or fingerlings or attempt to maintain own hatchery

3. Tilapia species and breeds F O. niloticus (Nile Tilapia) – Most commonly used tilapia 70-75% of global production F O. aureus (Blue Tilapia) about 5% of global production F O. mossambicus - (Mossambique or Java Tilapia) about 5% of global production F Red hybrid strains - O. mossambicus and/or O. urolepis-hornorum (Wami River Tilapia) crossed with O. aureus and/or O. niloticus) about 20% of global production

4. Tilapia species and breeds F Match fish to production system F Brackish water – Red hybrid strains F Pond systems – O. niloticus or red strains F Cage systems – O. niloticus or red strains F Intensive (tanks, raceways or recirculating systems) - O. niloticus or red strains F Cooler temperatures – O. aureus or hybrids F South Africa and California (only O. mossambicus and hybrids)

5. Genetic Improvements in Tilapia (From: Mair, G., 2002)

6. O. niloticus strains and breeding programs F G.I.F.T. - Genetically Improved Farmed Tilapia F Chitralada – From a strain kept at the Chitralada Royal Palace in Thailand F Genomar – A Norwegian-Brazilian breeding program F G.I.F.T.-EXCEL – Additional breeding program continued in the Philippines F At least 3 more family selection programs

7. Red Tilapia strains F Red O. mossambicus mutants found in 1970’s F Backcrossings fixed the mutation F Taiwan, Florida, Israeli, and Stirling (Scotland) strains were developed F These were repeatedly out-crossed to other species (New strains in Jamaica, Arizona, Colombia, Ecuador, Thailand, China, Vietnam) F Many red strains now available, most with high salinity tolerance

8. Methyltestosterone technique F Feed fry with food containing MT (60mg 17α-MT/kg of feed) for 21 days F For product to be sold in US, MT feed should be purchased from approved supplier F Females develop as males, males unaffected F Isotope labeling studies demonstrate that MT in fish is below detectable limits 30 days after last feeding F 90+ % develop as male fish

9. YY technique F Treat fry with estrogen F Males develop as females F These XY females are mated to normal males (XY) F ¼ XX : ½ XY : ¼ YY F XY and YY males are progeny tested to XX F Fathers of all male fry (XY) must be YY F YY males can be sold and crossed to normal females (XX) to get almost all male progeny (XY)

10. The YY male technology (GMT ® ) (From: Mair, G., 2002)

11. YY technique F FishGen, is a UK based company which sells YY males and fry from YY male hatcheries in several countries F Genetically Male Tilapia (GMT) is their brand name F Food fish are two generations removed from being treated with hormone and can be considered organic. F Technique could be copied, but hatchery would need several years and many qualified biologists to develop a program

12. Hybrid crosses F Several inter-specific crosses yield high proportion of males (70-90%) F Requires maintenance of two pure species breeding lines F This technique was developed in Israel and Chinese claim to do this with GIFT niloticus crossed with O. aureus. However, use of MT is suspected.

13. Hatchery styles F Normally stock 1♂ and 3♀ F Eggs are incubated by female F Eggs can be collected and hatched in jars or trays F Or hatched by mother and fry collected when free swimming

14. Dr. Raul Ponzoni and World Fish Center program in Malaysia.

15. Typical spawning or fry rearing hapas

16. Pond spawning vs. tank spawning F Pond or hapa rearing for large numbers F Tank spawning for small numbers and directed rearing programs

17. Jar and tray egg hatching F Jar hatching better for large numbers with little supervision F Tray hatching better if labor is abundant and high survival is important

18. Technologies to reduce externalities (MT use and discharge) F Reduce or eliminate MT use (mixed sex, cages, YY, hybrids, salt-water culture) F Use phytochemicals to induce sex change (still experimental) F Remove effluent MT with carbon, UV, or ozone

19. Post hatch F Swim-up fry allowed to leave hatching vessel F Usually collected in screened buckets or trays F Start sex reversal or start normal feeding in hapas

20. Fry moved to pre-growout around 1 g