1. Propagation Selected freshwater fish for aquaculture David Crisostomo DC Aquatic Systems Cooperative Extension Service University of Guam

2. General considerations Broodstock Broodstock Select only the best specimens for many characteristics…not just growth. Select only the best specimens for many characteristics…not just growth. Cull any fish with deformities, disease, low vigor Cull any fish with deformities, disease, low vigor Color, finnage, Color, finnage, Select from same age class to know who’s growing faster. Select from same age class to know who’s growing faster.

3. Broodstock Tanks - for tilapia Tanks - for tilapia Low density…a trio (2 females-1 male) of fish under 1 pound size can be placed in a 1600 liter tank Low density…a trio (2 females-1 male) of fish under 1 pound size can be placed in a 1600 liter tank Fish over 1 pound need a larger tank or reduce density to one pair. Fish over 1 pound need a larger tank or reduce density to one pair. Aeration should be mild. Aeration should be mild.

4. Sexing Broodstock Larger fish are easy to sex…smaller ones are more difficult. Larger fish are easy to sex…smaller ones are more difficult. Differences can be seen in the genital papilla. Differences can be seen in the genital papilla.

5. Breeding in large dirt ponds Males make nests in the bottom and try to court a female to breed. Males make nests in the bottom and try to court a female to breed. Males guard each nest Males guard each nest

6. Breeding Tilapia are allowed to breed naturally. In larger breeding tanks fish are placed at ratio of 3:1 (f:m). Tanks are seined every 3-4 days and females checked for eggs. Tilapia are allowed to breed naturally. In larger breeding tanks fish are placed at ratio of 3:1 (f:m). Tanks are seined every 3-4 days and females checked for eggs. Tilapia are mouth brooders….all eggs are laid on the bottom and then fertilized by the male. Tilapia are mouth brooders….all eggs are laid on the bottom and then fertilized by the male. Eggs are then picked up in the mouth of the female and kept there until about 4-5 days after they hatch. Eggs are then picked up in the mouth of the female and kept there until about 4-5 days after they hatch.

7. Collection and Incubation All eggs collected in one day are sorted according to their stage of development and placed in separate hatching jars. All eggs collected in one day are sorted according to their stage of development and placed in separate hatching jars.

8. Natural Spawning Breeders can be left to spawn and hatch the eggs and care for sac-fry Breeders can be left to spawn and hatch the eggs and care for sac-fry When fry are ready to be released the female will leave them. They will then swim to the surface in a tight school. They are very easy to scoop up at this point and are called “swim-up fry”. When fry are ready to be released the female will leave them. They will then swim to the surface in a tight school. They are very easy to scoop up at this point and are called “swim-up fry”.

9. Natural Spawning You must collect every fry. Any fry left will grow to the juvenile stage where they will begin to eat new fry produced. You must collect every fry. Any fry left will grow to the juvenile stage where they will begin to eat new fry produced. Adult fish won’t eat the new fry. Adult fish won’t eat the new fry.

10. Care of new fry Tilapia fry can readily accept artificial feed. They will do better if fed Artemia (brine shrimp). Tilapia fry can readily accept artificial feed. They will do better if fed Artemia (brine shrimp). If you wanted to produce all- male fry, now is the time to start them on the special feed. If you wanted to produce all- male fry, now is the time to start them on the special feed.

11. Sex-Reversal All male tilapia are usually used in commercial aquaculture because of their faster growth. All male tilapia are usually used in commercial aquaculture because of their faster growth. Tilapia are easily made to develop as all-males or all-females. Tilapia are easily made to develop as all-males or all-females. Fry are sexually undifferentiated…no sexual part developed yet. If fed a hormone treated feed for the first 30 days they will develop the sex organs based on the hormone used. Fry are sexually undifferentiated…no sexual part developed yet. If fed a hormone treated feed for the first 30 days they will develop the sex organs based on the hormone used.

12. Sex reversal warning! The culture of sex-reversed fish has been practiced by farmers in Asia, Guam and the US for at least 10 years. However, the administration of the hormone is very strictly limited to very few permitees in the US. The culture of sex-reversed fish has been practiced by farmers in Asia, Guam and the US for at least 10 years. However, the administration of the hormone is very strictly limited to very few permitees in the US. Asian hatcheries still produce their own sex- reversed fry and sell to Guam/US farms. Asian hatcheries still produce their own sex- reversed fry and sell to Guam/US farms. Legal to purchase sex-reversed fry from Asia, but not to produce it yourself…???? FDA regulations Legal to purchase sex-reversed fry from Asia, but not to produce it yourself…???? FDA regulations If caught with the hormone, you could get jail time…it’s a Schedule 2 drug. If caught with the hormone, you could get jail time…it’s a Schedule 2 drug.

13. Clarias Catfish Also called “Walking catfish” because it can travel over land for some distance. Also called “Walking catfish” because it can travel over land for some distance. Is prohibited from being transported across state or territorial lines. Very aggressive fish and extremely hardy. Is prohibited from being transported across state or territorial lines. Very aggressive fish and extremely hardy. Often difficult to kill. Protect fry in nesting area. Often difficult to kill. Protect fry in nesting area. Can breath out of water. Can breath out of water.

14. Sexing Catfish Males and females are easy to distinguish based on the shape of their genital structures. Males and females are easy to distinguish based on the shape of their genital structures. Male papilla Female oviduct

15. Breeding catfish Catfish are allowed to mature and develop eggs in an undisturbed large pond or tank. Catfish are allowed to mature and develop eggs in an undisturbed large pond or tank. When females are full with they are moved to a holding tank. Eggs are drawn out and checked for development. When females are full with they are moved to a holding tank. Eggs are drawn out and checked for development. If ready, she is injected with CPE (Carp Pituitary Extract) or HCG (Human Chorionic Gonadotropin) in 2 doses, 6 hours apart. She will begin releasing eggs within 2-4 hours after the 2nd injection. If ready, she is injected with CPE (Carp Pituitary Extract) or HCG (Human Chorionic Gonadotropin) in 2 doses, 6 hours apart. She will begin releasing eggs within 2-4 hours after the 2nd injection. Males are also injected once to assure they will have good sperm production. Males are also injected once to assure they will have good sperm production.

16. Stripping eggs When female begins releasing eggs she is stripped and eggs collected in a bowl with NO water. When female begins releasing eggs she is stripped and eggs collected in a bowl with NO water. Contact with water will begin a hardening process in the eggs and reduce fertilization. Contact with water will begin a hardening process in the eggs and reduce fertilization.

17. Dry Fertilization Males are sacrificed and their testes removed. Testes are cut open over the eggs and sperm are deposited on eggs. Water is added to just cover eggs and contents are mixed very gently for a few minutes Small airstone is placed in mixture with very gentle aeration. Mixture is allowed to sit for 5 minutes Eggs are then poured onto screen on floor of tank

18. Hatching and fry care Eggs hatch after about 24 hours. Eggs hatch after about 24 hours. New sac fry cant swim for about 2 days. New sac fry cant swim for about 2 days. On 3rd day begin light feeding with Artemia (brine shrimp) On 3rd day begin light feeding with Artemia (brine shrimp) Fry grow very fast, but at different rates Fry grow very fast, but at different rates Larger fry must be removed or they will start eating smaller fry. Larger fry must be removed or they will start eating smaller fry. Stock into grow-out tank after 2 weeks. Stock into grow-out tank after 2 weeks. Feed fry feed for 2 more weeks, then larger feed. Feed fry feed for 2 more weeks, then larger feed.

19. Shrimp/Prawns Shrimp are generally hatched in commercial hatcheries due to their more complex larval cycle and specialized feed. Shrimp are generally hatched in commercial hatcheries due to their more complex larval cycle and specialized feed. I’ll describe the process generally for marine shrimp. I’ll describe the process generally for marine shrimp. Breeders are maintained in a tank with good supply of clean seawater. Breeders are maintained in a tank with good supply of clean seawater.

20. Marine Shrimp When shrimp mature, males begin chasing female until one is allowed to mate. The male deposits a spermatophore (sperm packet) on the underside of the female. That ends the mating process. The female then swims around and releases eggs. As they are released they contact the sperm and get fertilized. When shrimp mature, males begin chasing female until one is allowed to mate. The male deposits a spermatophore (sperm packet) on the underside of the female. That ends the mating process. The female then swims around and releases eggs. As they are released they contact the sperm and get fertilized.

21. Marine shrimp Eggs are released into the water. After a day they hatch. Eggs are released into the water. After a day they hatch. They are fed phytoplankton a couple of times daily to maintain a specifc phytoplankton density. They are fed phytoplankton a couple of times daily to maintain a specifc phytoplankton density. As they get larger they are fed newly hatch Artemia. About 1 month post hatch they transform to the post larval stage. As they get larger they are fed newly hatch Artemia. About 1 month post hatch they transform to the post larval stage. One week after this transformation they can be stocked into grow out ponds. One week after this transformation they can be stocked into grow out ponds.

22. Ornamental fish culture Ornamental fishs are comprised of 1500 varieties. Ornamental fishs are comprised of 1500 varieties. Spawning strategies are widely varied. Spawning strategies are widely varied. Live bearers and egg layers. Live bearers and egg layers. Ornamental producers must always have a hatchery Ornamental producers must always have a hatchery

23. Live Bearers This group are considered the bread and butter group because they are easiest tp spawn. Fry are large enough when born to accept artificial feed. This group are considered the bread and butter group because they are easiest tp spawn. Fry are large enough when born to accept artificial feed. Fry must be protected from predation from adults Fry must be protected from predation from adults Fry are matured in 3-4 months and can be marketed. Fry are matured in 3-4 months and can be marketed.

24. Egg Layers Egg layers have many different strategies…from substrate spawners to bubble nest spawners to mouthbrooders. Egg layers have many different strategies…from substrate spawners to bubble nest spawners to mouthbrooders. These include angelfish, bettas, gouramis, catfish, cichlids and others. These include angelfish, bettas, gouramis, catfish, cichlids and others. Egg Layers produce many more fry than live bearers Egg Layers produce many more fry than live bearers Fry are smaller in egglayers and subject to predation. Fry are smaller in egglayers and subject to predation.