Evaluation of feeding rate based on growth,feed conversion,protein gain and carcass quality of fingerling Indian major carp,Catla catla (Hamilton)

The effects of feeding rates on growth, feed conversion, protein deposition and carcass quality of fingerling Catla catla (3.61 ± 0.03 cm; 0.71 ± 0.04 g) were worked out by conducting a 16‐week feeding trial. Fingerlings were fed with a casein‐gelatin‐based purified diet (40% crude protein CP; 14.95 MJ kg^?1 digestible energy; DE) at 1%, 2%, 3%, 4%, 5%, 6% and 7% body weight per day. The absolute weight gain (AWG; 10.50 g fish^?1) and feed conversion ratio (FCR; 1.41) were highest at the feeding rate of 5% body weight per day. However, protein gain (PG; 0.36 g fish^?1) and carcass protein content attained the maximum values at 4% BW day^?1. Quadratic regression analyses of AWG g fish^?1 and PG g fish^?1 at 95% maximum response indicated that these parameters attained the best values at 4.19% and 3.81% BW day^?1. On the basis of the above results it is recommended that the feeding rate in the range of 3.81–4.19% BW day^?1 with a P:E ratio of 26.69–27.74 mg protein MJ^?1 DE is optimum for maximum growth, efficient feed conversion and best carcass quality in fingerling C. catla.     

配合饲料高密度培育一龄胭脂鱼种的研究

研究了投喂配合饲料,在水泥池中高密度养殖胭脂鱼鱼种的技术,结果表明:胭脂鱼成活率90.06%,饵料系数2.086 0。并且得出脂胭鱼全长、体重关系式Y=0.044X2.604 5(R2=0.804 3)。     

Influence of water exchange rates on fingerling production in Indian major carps in large outdoor concrete tanks

Influence of varied water exchange (total of 0%, 40%, 60%, 80% and 100% in four phases during three months) on fingerling production of Indian major carps-catla, rohu and mrigal under polyculture was evaluated in large outdoor concrete tanks (50 m²). Rearing density of 30 fry m⁻³ was used. Survival in the control tanks reduced during the 2nd month unlike the treatments, attributed to lack of water exchange in the tanks. While no marked variation in water quality was observed among the control and treatments, graded water exchange led to proportionate improvement in the fingerling performance in terms of survival and growth in the treatments. Harvested total lengths of fingerlings were similar in all, irrespective of varied exchange levels. Although no significant variation in net weight gain (NWG) and specific growth rate (SGR) were observed among the treatments during 1st and 2nd months of rearing in any of the species, these attributes increased significantly during 3rd month with higher water exchange in treatments. The harvested body weight (HBW) also increased significantly with increased exchange level. However, survival, HBW, NWG and SGR remained similar in all species between the 80% and 100% water exchange levels. Treatment with 80% water exchange had higher water productivity in terms of number and biomass production of fingerlings per unit (m⁻³) of TWU and CWU for which, the study recommended 80% to be the ideal total water exchange required for fingerling production of IMC in concrete tanks.     

The cause of death of juvenile Pacific bluefin tuna (Thunnus orientalis) reared in sea net cages

Although the survival rate of juvenile Pacific bluefin tuna Thunnus orientalis (PBT) during 30 days after stocking in sea net cages has been as low as approximately 50%, the reason for this high mortality is not clear. The dead fish were collected and counted during 30 days after stocking in a sea net cage, and the growth performance, stomach contents, and bone injury were investigated. Nearly half (47.9%) had died within the first 4 days. The total length and body weight of the dead fish were significantly smaller than those of the live fish, and the weight of the dead fish did not increase during the first 7 days. Approximately one-third of the dead fish (21.9–42.9% per day) had ingested inorganic matter such as wood or Styrofoam waste during the first 7 days, and 25.0–45.0% of the dead fish sampled per day showed poor growth. The daily ingestion rate of inorganic matter decreased dramatically from the eighth day, when the daily mortality rate decreased. The percentage of dead fish with bone injuries due to collision or contact was low (less than 15%). These results suggest that one of the causes of high mortality during several days after stocking in a sea cage was accidental ingestion of inorganic matter by juvenile PBT. Improvement in feeding method can increase the survival rate of juveniles in sea net cages.     

池塘培育大眼狮鲈鱼苗、鱼种的试验

哈尔滨市水产研究所于1993年5月24日从加拿大FortQu′Appelle鱼苗孵化场移运大眼狮鲈鱼发现鱼卵，经孵化后孵出鱼苗14万尾，在池塘中培育。鱼苗阶段培育36天，体长53．9mm，成活率75％；鱼种阶段经95－100天培育，套养的鱼种体长20－22．5cm，体重83－107．4g，单养的鱼种体长17．5cm，体重48．4g。     

Nile tilapia (Oreochromis niloticus) seed production in irrigated rice-fields in Northwest Bangladesh—an approach appropriate for poorer farmers?

Participatory research was conducted with poorer farmers in two communities, Girai (G) and Bahagili (B) in NW Bangladesh to assess the production of Nile tilapia seed in irrigated spring rice-fields. All the selected households (G = 15; B = 4) had previous experience producing common carp (Cyprinus carpio) in the rice-fields allocated a separate plot in which a deeper area had been excavated for this trial. Mature GIFT strain Nile tilapia (12 female and 6 male; 121 ± 34 g and 158 ± 54 g size, respectively) were supplied to each household irrespective of the size of their trial plot (mean < 0.15 ha). The trial started in the spring rice season (boro) in February and ended at the end of main season (amon) in December 1999. Management practices, production and sales of fish were monitored weekly.The majority of farmers succeeded in producing fingerlings in their plots; 11% failed totally but around 70% produced more than 2000 fingerlings from a single plot. Production during boro and fallow period was much higher (> 90% total) than during the subsequent amon crop (< 10% total). Total production was highly variable among households but not different between the two study areas (G = 4092 ± 3277; B = 3730 ± 4232 fingerlings household^− 1). Daily production of fingerlings per unit area was relatively low (< 1 fish m^− 2 day^− 1) but efficiency of production was high, averaging 17.3 fingerlings. kg^− 1 female day^− 1. Mean individual harvest weight was 21 g.Most fingerlings were sold (43%) and/or stocked for further culture in their own grow-out system (39%), but some were used directly for household consumption (17%).     

翘嘴红鲌水花及鱼种饲料的设计与苗种培育

参照国内现有翘嘴红鲌营养需求及饲料原料消化率的研究成果,设计了翘嘴红鲌水花、夏花鱼种配合饲料的主要营养素指标;应用配方软件优化,得出了水花、夏花鱼种的配合饲料配方并用于试产。产品经检测,主要营养素指标为:水花饲料粗蛋白44.3%,粗脂肪8.4%,粗纤维4.6%,总磷1.43%,赖氨酸2.55%,蛋氨酸0.71%,苏氨酸1.67%;夏花饲料粗蛋白40.8%,粗脂肪6.7%,粗纤维6.6%,总磷1.21%,赖氨酸2.42%,蛋氨酸0.62%,苏氨酸1.52%。苗种培育试验证明:用自行研制的水花饲料培育成夏花的成活率平均为83.0%;鱼种饲料培育成冬片鱼种,成活率平均为93.45%,出塘规格平均全长为14.2 cm,体重15.4 g,饵料系数平均为1.21,显著好于从市场购进的水花、鱼种饲料。     

Influence of duration of aeration on growth and survival of carp fingerlings during high density seed rearing

Impact of varied durations of aeration on growth, survival and production performances of catla (Catla catla), rohu (Labeo rohita), fringe lipped carp (Labeo fimbriatus) and olive barb (Puntius sarana) were evaluated in outdoor concrete tanks (10 m × 5 m × 1.3 m) during fingerlings rearing. At a combined stocking density of 0.5 million fry/ha, provision of night time aeration for 4, 8 and 12 h was evaluated as the three treatments, T-I, T-II and T-III, respectively against control (T-c, without aeration). Overall survival and net biomass of the species increased among the treatments significantly as a function of aeration hours (T-c < T-I < T-II < T-III). Aeration for 8 and 12 h showed significantly higher survival, harvested body weight and SGR in all the carps than those with 4 h (T-I) and no aeration (T-c), suggesting 8–12 h of aeration requirement for fingerlings rearing at such high density. Further, no significant difference between survival levels in T-II and T-III groups suggested 8 h of aeration to be adequate. However, while species-wise performance showed 8–12 h night time aeration to be advantageous for catla and rohu, aeration for 4 h was adequate for fringe lipped carp and olive barb.     

西江三角鲤人工繁殖技术研究

本研究使用广西水产研究所池塘人工驯化饲育三年的天然西江三角鲤亲鱼1676尾,采用经筛选的鱼类敏感药物(PG、LHRH-A2、HCG)单一或混合催产的方法,在2002~2005年,先后进行了10批共600组的西江三角鲤人工繁殖试验。收集受精卵795.5万粒,在水温20.0~28.5℃条件下,利用环道池孵化出稚鱼680.9万尾,平均孵化率为85.6%。并使用日产光学显微镜观察了自授精卵至稚鱼破膜而出的发育全过程,拍摄了各个阶段胚胎发育的图谱16幅。培育出2.5cm以上鱼种631.7万尾,平均成活率达92.8%。     

疏浚泥浆排放对渔业生产的影响 及其对策研究↑（*）Ⅱ．对鱼苗、鱼种呼吸代谢、血液生化指标和鳃组织结构的影响

以鲫、草鱼、鲢和团头鲂鱼种为材料，研究了疏浚泥浆对这些鱼类的耗氧率、血液学生化指标和鳃组织结构变化的影响。结果表明，在泥浆浓度0．08－1．248g／l范围内、鱼种的耗氧率（Y）与水体含泥量（X）呈线性相关，其关系式为：Y↓（鲫）=0．3324－0．0745X（P＜0．01），Y↓（