Seed production of the indigenous fish, Spinibarbus denticulatus, in North Vietnam | |
| Author | Dinh Van Trung |
| Call Number | AIT Diss. no.AQ-08-02 |
| Subject(s) | Cage aquaculture--Vietnam Carp fisheries--Vietnam |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Technical Science in Aquaculture and Aquatic Resources Management, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. AQ-08-02 |
| Abstract | The carp, Spinibarbus denticulatus (Oshima) has significant potential for aquaculture, particularly in low-input systems relevant for developing countries. With the local name 'Ca bong', S. denticulatus is indigenous to North Vietnam. Although, some pond and cage stocking is done from wild collected seed, no studies on its life history or habitat description have been published to date. Moreover, culture of this species is constrained by the limited supply of wild seed. A comprehensive study was undertaken to understand, 1) current culture practices of wild caught fry and fingerlings, 2) main reproductive characteristics of this species, 3) the potential of induced breeding using commercially available hormones, and 4) the use of locally available natural and artificial feed for larval rearIng. A formal survey on culture practices of S. denticulatus in the North Vietnam was conducted in the mountainous provinces of Tuyen Quang ( cage culture) and Ha Giang (pond culture). A total of 129 households were interviewed. Through the fishery extension program, 30% of the farmers of Ha Giang and 100% of the farmers in Tuyen Quang had been trained in aquaculture. In the pond culture system, leaves of cassava & banana, grass, vegetable and manures were used to feed at 3.3% BW. Polyculture with Chinese carps and Indian major carps was common with production ranged from 35 to 300 kg/ha. Size of S. denticulatus was small at stocking (0.3-lg fish⁻¹) and culture period ranged from 4 to 6 years before harvest. In the cage systems, both monoculture (59%) and poly-culture (41 %) with Ctenopharyngodon idella, S. denticulatus and Bagarius yarrelli were practiced. Production of C. idella ranged from 80 to 1000 kg per 2 to 15m³cage. All fingerlings of S. denticulatus were collected from the wild sources. The two most difficult problems facing the interviewed farmers were, 1) year round availability of stocking size fry (for ponds) and fingerlings (for cages) and, 2) slow growth. A preliminary set of studies was conducted to understand some of the basic reproduction parameters of this species as a prelude to more specific research studies, and the subsequent development of hatchery technology. Gonad and oocyte development was assessed over a 12 month period. Observation of the annuli rings of the fish scale was found to be a reliable way to measure fish age. Mature males were smaller and matured earlier (4 years) than females (5 years). The gonadosomatic index revealed two peaks (April and October). Oocytes were examined from January to March .. In January the oocytes sizes were uniformly small. Two distinct oocyte-size groups were observed in the February sampling and three size groups were observed in March. During the near peak spawning months, the proportion of large-size oocytes (55%) was higher compared to mid-size (26%) and small-size (19%) oocytes. The mean sperm concentration was 8.42 ± 0.36 million cells per ml with only a small amount (3.3 ± 0.2 ml) of total expressible milt per male. However, when induced with LHRHa the milt production increased to 6.2 ± 0.5 ml without an increase in the total number of sperm cells. The species showed potential for mass production; however, they did not naturally reproduce in captivity even after holding both sexes in ponds for 3 years after maturation. Since these fish do not naturally breed in captivity, carp pituitary extract (CPE), luteinizing hormone-releasing hormone analogue (LHRHa) with domperidone (DOM) and human chorionic gonadotropin (HCG) were administered at various doses to induce ovulation. A first set of experiments evaluated the response to LHRHa (30, 40 and 50 ug kg⁻¹) with or without DOM (10 mg kg⁻¹), CPE (20, 30 and 40 mg kg⁻¹), and HCG (3000, 4000 and 5000 IU kg⁻¹). A second set of experiments evaluated the dose response LHRHa (30, 35, 40 and 50 ug kg⁻¹) primed with 6 mg kg⁻¹ of CPE, and HCG (30 3500, 4000, 5000 IU kg⁻¹) primed with 6 mg kg⁻¹ of CPE. The treatment groups w compared to each other and the control (injected with 0.9% saline solution). LHRH, DOM (40 ug kg⁻¹ + 10.0 mg kg⁻¹) and CPE (30 mg kg⁻¹) are most effective in consister inducing ovulation and thus could be used for commercial hatchery production. The use of combined hormone strategy has no apparent advantage over single hormone strate, Fertilization and hatch rates observed in this study with different hormonal stimulat were high (80-93%). A study of relevant nutntlon requirements and food types for the nursery stage of denticulatus was undertaken. The study consisted of two experiments. In the first one, the 7 day old swim-up fries (11 ± 0.1 cm in length and 0.02 ± 0.00g in weight) were stock at the three densities of 200, 250 and 300 fry per 1m³ hapa. They were fed powder feeds of 30% and 40% protein and additional soy bean oil of I % and 2%., Two feeding ratio] 10% and 20% body weight (BW) day⁻¹ were applied for 55 days. In the seco experiment, the powder feeds were compared with live food mixture (97.% zooplankt and 8% phytoplankton collected from a manure fertilized pond) after 65 days of cultu In the first experiment, at each feeding ration, the growth and survival rates of fingerlin were not affected by 30% and 40% protein or 1 % and 2% lipids. But there were significant differences in growth and survival between two feeding rations (10% a 20%BW). The higher weight increase (0.32 ± 0.04g) and survival (81.6%) were obtain tn the treatments fed 20% BW. The weight increase was 0.26 ± 0.00g and survival was 63.5% respectively, in the treatments fed 10% BW. In the second experiment, the highest weight increase (0.46 ± 0.0 lg) and higher survival (88.2%) were found in live food treated group. This study indicates that the protein requirement at nursery stage is not 1igh compared with other carp species of similar age. The live foods enhanced t mrvival and percent growth for S denticulatus at the nursery stages. |
| Year | 2008 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. AQ-08-02 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Bart, Amrit N.; |
| Examination Committee(s) | Rakshit, Sudip K.;Gallardo, Wenresti G.;Edwards, Peter; |
| Scholarship Donor(s) | DANIDA; |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2008 |