Fish reproduction and hatchery managment.pptx

Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva.
Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry.
Brine shrimp live in hypersaline lakes in which the salt content may be 25%, predators and competitors are few, and algal production is high.

1. Sokoine university of agriculture (SUA) Fish reproduction and hatchery maNAGEMENT ARTEMIA PRODUCTION IN PONDS NAME: MAGOTI ERNEST

2. INRODUCTION Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish , crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry . Brine shrimp live in hypersaline lakes in which the salt content may be 25% , predators and competitors are few , and algal production is high .

3. Optimum conditions for hatching Artemia cysts are; Temperature less than 34 o C Salinity of 800-100 ppt Continuous aeration pH of about 8 Pond depth 40cm – 50cm Green water (phytoplankton rich- water)

4. Artemia Production Artemia are mostly used as freshly hatched nauplii or enriched nauplii fed emulsified lipid diets or algae for a period of 24 hours . Juvenile and preadult/adult Artemia have also been used for first feeding of some species such as halibut , shrimp and lobster larvae . Biomass from harvested Artemia is also used for feeding several species of penaeid shrimp and other freshwater fish species even though fresh live forms have the highest nutritional value

5. Diagram below shows the culture area, total production and yield of Artemia cysts ( raw products) in Vietnam

6. Culturing Procedures Artemia cysts are placed in seawater. Aeration and a light source are provided and allowed to hatch (usually within 24 hours). Freshly hatched Artemia nauplii are then separated from empty shells and debris by removing the aeration and allowing settling to occur. Artemia cysts are usually disinfected with a dip into chlorine or they may be decapsulated using chlorine.

7. Artemia production in ponds Site selection Topography , soil condition , dike system , drain and canal system as well as climate are important parameters for proper site selection of Artemia production in ponds.

8. Selection of Artemia strain A. franciscana is usually used for pond production in solar salt farms. T his species has higher colonizing abilities than other species. Cysts of this species have excellent quality characteristics , e.g. small in size , high hatching and nutritional qualities particularly its content of highly unsaturated fatty acids (HUFA). It is critical to inoculate Artemia nauplii in the instar I stage in salt ponds of 70 g/L salinity and higher. Only in this instar I stage Artemia nauplii can survive sudden salinity shocks.

9. Suitable time of stocking The best stocking time is in the early morning (7-8 am) or in the evening (5-7 pm) considering relatively cool water temperature . Suitable places to release newly hatched Artemia Artemia nauplii is suitable to spread evenly all over the pond surface. It is required to check the nauplii density next morning through sampling. Stocking strategy Good production result are obtained when inoculating 50-70 nauplii/ L into pond water salinity 70 g/L . One can also inoculate at higher densities (up to 500 nauplii/L) in a small pond area under optimal culture conditions (water depth and food availability) and after 1 week of culture transfer to a larger pond .

10. Harvesting management Artemia can be harvested under 2 forms; cysts and biomass Harvesting requires to consider suitable time, frequency and ensure best quality of the products. Artemia biomass has longer culture period than Artemia cyst considering the seasonality and preparation time. Salinity and feed management require to be in accordance with preference of Artemia cyst and or biomass production .