HCG and LHRH-A induced spawning in bighead carp Aristichthys nobilis Rich. reared in floating cages in Laguna de Bay
MetadataShow full item record
Hormone-induction of spawning in bighead carp Aristichthys nobilis Rich. by single or double intraperitoneal injection with varying combined dosages of HCG and LHRH-A was conducted. Fish were spawned successfully following a single or double injection with 1800 to 2000 IU HCG in combination with 10, 15 or 20 µg HRLR-A per kg body weight. Fish injected with lower dosages of HGC at 1200 or 1500 IU/kg body weight plus 20 µg/kg LHRH-A did not differ significantly (P>0.05). Fish given a single injection ovulated after 12.0 ± 0.1 hours. No significant difference was found in the total number of eggs spawned per fish among the injection protocols (P>0.05). However, lower fertilization and hatching rates of eggs were observed in fish that spawned spontaneously in the tank as compared to those fish whose eggs were stripped and dry-fertilized (P<0.05).
CitationFermin, A. C., & Reyes Jr., D. M. (1989). HCG and LHRH-A induced spawning in bighead carp Aristichthys nobilis Rich. reared in floating cages in Laguna de Bay.
PublisherSan Carlos Publications, University of San Carlos
Showing items related by title, author, creator and subject.
ArticleMY Tabbu, MM Lijauco, RV Eguia & CC Espegadera -
Fisheries Research Journal of the Philippines, 1986 - Fisheries Research Society of the PhilippinesIncreasing fish production through polyculture was clearly demonstrated to the fishfarmers in Laguna lake. The rearing of different species of fish of proper number and species combinations had resulted to the efficient utilization of all the available food niches/zones in the lake. Fish production is site specific in Laguna lake. Wide variation in growth increment and fish yield were observed among the different bays and among farm sited within a bay. The final mean weights of the fish species were 355 mg to 2300 g for bighead carp, 32 g to 103.3 g for tilapia and 8.3 g to 1800 g for common carp.
Conference paperAC Fermin - In JV Juario & LV Benitez (Eds.), Seminar on Aquaculture Development in Southeast Asia, 8-12 September 1987, Iloilo City, Philippines, 1988 - SEAFDEC Aquaculture DepartmentBighead (Aristichthys nobilis) and silver (Hypophthalmichthys molitrix) carps were reared in ponds, pens and floating cages in Laguna Lake until maturity. Spontaneous gonadal maturation and rematuration of carp broodstock occurred within 2-2.5 years with average weight of 3-4 kg. Under lake conditions, broodstock were not given supplemental feeds. Induced spawning of gravid females was done by intraperitoneal injections using HCG combined with either common carp pituitary homogenates or LHRH-A. Stripping and dry-fertilization of eggs were done 6-8 hr after the final injection. Eggs were incubated in water containing 300-500 ppm Total Hardness. Fertilization and hatching rates were 23-88% and 7-36%, respectively. Post-larval carps were reared in tanks and fine-meshed nylon net cages installed in manured ponds. Tank-reared post-larvae were fed with Brachionus plicatilis and subsequently with Moina macrocopa in combination with powered formulated feeds containing 40% crude protein. Fry were harvested and stocked in nursery cages after 30-45 days of rearing in tanks. Four-month old 50-100 g tilapia (Oreochromis niloticus) stocked in hapa net cages, tanks or ponds were used for breeding. Egg and fry production was significantly high at 4 females/m2 stocking density Different sex ratios, however, did not affect fry production. Spawning frequency and total growth of broodstock was highest in fry fed formulated diets containing 50% crude protein. Harvesting of fry was done every 15 days during summer months and every 21 days during cold months. Fry were reared in tanks and hapa cages and fed diets containing 35% crude protein. Supplemental feeding in the lake was suspended when productivity reached 3 gC/m2 /day.
The effects of water hardness on the hatching and viability of silver carp (Hypophthalmichthys molitrix) eggs An investigation was conducted to establish water hardness concentration for optimum hatching of silver carp (Hypophthalmichthys molitrix) eggs. Eggs were incubated for 19 h at 26.5°C at six levels of water hardness: 100, 200, 300, 400, 500 and 600 mg/l CaCO3. Water absorption at 100–200 mg/l CaCO3 caused eggs to burst prematurely and minimal water absorption occurred at 600 mg/l CaCO3. Chloride concentration at 0 and 6 h post-fertilization was significantly related to egg hatchability. Total ammonia-nitrogen at 6 h, pH at 6 h, magnesium hardness at 18 h and chlorides at 18 h significantly influence viability of larvae. A water hardness of 300–500 mg/l CaCO3 is recommended for the successful hatching of silver carp eggs.