Saline Tilapia (Oreochromis sp) Broodstock Production :  Growth and Reproductive Performance as effort the seed supply for culture

Mohamad Soleh*, Agustien N**. dan Khaemudin***
 
Main Center for Brackhiswater Aquaculture Develompmet
Email : bbpbapjpr@gmail.com

Recently saline or salt tilapia (Oreochromis sp) is not as a local cunsume only but is once of an export commodity with high value right now.  Initially this species as a biofiltre on shrimp brackiswater culture and then as culture species in pond and  floating net system in the sea as well.  Concerning to high salinity, freshwater tilapias offspring have low tolerance so it was important prepared from high salinity tolerance of broodstock.  Center For Brackishwater Fisheries Aquaculture Jepara has produced some strain saline tilapias broodstock and offspring as well and during its rearing in the sea water.

The aim of the experiment is to produce saline tilapias broodstock (high salinity tolerance) through direct stress test  in high salinity (35 ppt) on freshwater offspring populations.

Methods of it broodstock production was executed by rearing freshwater offspring of genetic improvement till size which is ready to spawn.  Initial step is direct stressed to the freshwater offsprings (size 3-5 cm/pcs) in high salinity (35 ppt) during 2 hours or if the  population remain around 50 %.  Secondly, rearing live offsprings in the sea water till broodstock size. , The fish take place in the conctreat tank,  volume 4 m3 and stocking density is 4-5 pcs/m2.  The fish fed by commercial pellet (25 % protein content, dosage 15-4 % biomass, 3 times a day) and enriched by enzyme of papaya extract (dosage 50 ml/kg of food). The strain of the  fish are  Gesit or Sultana, Kunti and Srikandi (black tilapia) and Larasati (red tilapia) . Spawning of the breeder in  water salinity 10-15 ppt, male and female ratio is 1:3.  Food dosage is 1-2 % of biomass a day and frequency 3 times.  Water exchange by circulation system.

Result showed that broodstock of Gesit/Sultana strain (black tilapia) growth fastes more than Larasati strain (red tilapia) is 4 months and 6 months, respectively. The average final body weight  is  152.2316 g/pcs , survival rate is 61.1 %, FCR is 1:2.4548 and ADG is 2.07 (Gesit/Sultana strain) while Larasati strain is  144.2467 g/pcs, survival rate is 50.23 %, FCR is 1:4.757 and ADG is 0.6860.  Comparing an average productivities of eggs or larvae/g body weight of broodstock among black tilapia : Gesit/Sultana, Kunti and Srikandi strain are 4.47;  3.78 and 2.78, respectively. Thoose data obtained  from 27 samples, 13 samples and 4 samples.  In freshwater (salinity 0 ppt) spawning, Gesit/Sultana strain produced 3.84 eggs or larvae/g body weight of brooder (from 8 samples).