OBSERVATION ON THE INDUCED SPAWNING PRACTICES IN THE HATCHERIES OF RAJSHAHI DISTRICT OF BANGLADESH
An investigation was conducted during the period from March to December 2009 to investigate the induced spawning practices in 22 hatcheries of 6 Upazilas of Rajshahi District of Bangladesh. It was observed that, 6 native fish species viz. rui ( Labeo rohita ), catla ( Catla catla ), mrigal ( Cirrhina mrigala ), calibaush ( Labeo calbasu ), bata ( Labeo bata ), gonia ( Labeo gonius ) and six exotic fish species such as silver carp ( Hypophthalmichthys moltrix ), bighead carp ( Aristichthys nobilis ), grass carp ( Ctenopharyngodon idella ), common carp ( Cyprinus carpio ), Thai pangus ( Pangasius sutchi ), rajputi ( Puntius gonionotus ) were used in the surveyed hatcheries for induced spawning purpose. The average length limit was 41.70±13.02 to 72.81±25.98 cm, average age limit was 1.96±0.75 to 3.08±0.90 years and average weight limit was 1.83±0.79 to 7.54±3.92 kg of the brood fish. Two types of hormone injections like PG (pituitary gland) and HCG (human chorionic gonadotropin) were used for induced spawning. The rate of 1st doses of injections of PG were from 1 to 4 mg/kg and HCG from 150 to 500 IU/kg and the rate of 2nd doses of injections of PG for native and exotic species were from 4 to 8 mg/kg and 4 to 10 mg/kg respectively. The incubation period and hatching rate in different fish species varied from 10 to 72 hours and 55% to 80%, respectively. DOI: http://dx.doi.org/10.3329/jles.v6i0.9723 JLES 2011 6: 65-68
Efficacy of two inducing agents PG and DoM+SGnRH in the induced breeding of the major carp, kalibaus (Labeo calbasu).
An experiment on the induced breeding of the endangered fish, Labeo calbasu (Hamilton-Buchanam) was conducted in the Fish Seed Multiplication Farm,Rajshahi to know the efficacy of two inducing agents (PG and DoM+SGnRH). Three breeding trials of each inducing agent were performed. A total of 24 females weighing from 1.5 kg to 2 kg were given an initial and a resolving dose of 1.5 mg and 6 mg PG extract per kg body weight respectively as treatment-1. On the other hand, a total of 24 females weighing from 1.5 kg to 2 kg were given a single dose of 12 mg DoM + SGnRH/kg as treatment-2. In case of treatment-1, 12 males weighing from 1.5 kg to 1.95 kg were administered a single dose of 1.5 mg PG/kg body weight during resolving dose of female. In treatment-2, 12 males weighing from 1.5 kg to 1.8 kg were administered 3 mg DoM+SGnRH /kg body weight during initial dose of females. In treatment-1, the time interval between initial and resolving dose was 5 hours and ovulation occurred in all the injected females within 6 hours after resolving dose. Ovulation occurred within 6 to 8 hours after the injection of inducing agents for treatment-2. The mean rates of ovulation, fertilization and hatching were 100%, 77.36% and 74.5% respectively in treatment-1. On the contrary, the mean rates of ovulation, fertilization and hatching were 83.33%, 63.83% and 59.66% in treatment-2. Hatchery produced fry were reared in nursery pond for 40 days. In nursery pond. Flour, oil cake and wheat bran were applied as nursery feeds. Both the inducing agents were effective in respect of overall breeding performance. But the best results were obtained with PG although in case of DoM+SGnRH complete breeding takes place within short time with less labour and cost than that of PG . DOI: http://dx.doi.org/10.3329/ujzru.v31i0.15376 Univ. j. zool. Rajshahi Univ. Vol. 31, 2012 pp. 23-26
A Hatchery Manual for the Common, Chinese and Indian Major Carps
This major work on carp hatchery and nursery methods was part of an Asian Development Bank (ADB) project to improve carp seed production technology in ADB-member countries notably Bangladesh, Burma, Indonesia, Nepal, Pakistan and Sri Lanka. Designed as a reference source on carp seed production and as a mini-library for those stationed at seed production centers remote from scientific information channels.