网箱培育海参苗技术

随着海参增养殖业的发展,对海参苗的需求量也在不断增加。目前,海参养殖的苗种来源是通过工厂化育苗来提供,而工厂化育苗的生态环境比较稳定,同时也就保护了弱势群体,人为地减少了海参苗的自然淘汰,在这种条件下繁育的海参苗,成活率比较高,但是,把在这种条件下繁育的海参苗投放到自然环境中养殖,成活率偏低,只有5%～15%。     

我国海参池塘养殖存在的问题及应对措施

进入21世纪我国在经历了以海带、对虾、扇贝、海洋鱼类为代表的四次海水养殖浪潮之后,海水养殖业迎来了以海参为代表的第五次浪潮。目前我国海水养殖业正朝着多品种、多元化的可持续方向发展,海参养殖已发展成为我国海水养殖业中的一个重要产业。近年来,随着海参养殖业的高速发展,出现了多种海参养殖方式:围堰养殖、池塘养殖、网箱养殖、室内工厂化养     

一元二氧化氯在海参苗种培育中的应用

近年来,海参育苗与养殖在北方地区发展很快,育苗场不断增多,有关育苗技术也得到了深入的研究,笔者在2006年海参工厂化育苗过程中使用了稳定性一元二氧化氯,对育苗池水进行消毒杀菌处理,取得了较好的效果,培育出的海参苗规格整齐,体质健壮,生长较快,用户购买后反映良好。     

浅谈我国海参工厂化养殖技术

<正>随着经济的发展和人们生活水平的提高,对海参的需求量越来越大。自然产的海参越来越少,人工养殖得到了空前的发展。尤其是近年来,养殖企业和养殖户越来越多地尝试工厂化养殖,克服现有养海参方式的缺点和弊病,完善海参养殖工艺,降低海参养殖成本,缩短海参养殖周期,以推进海参养殖业的快速发展。     

江苏赣榆县青口刺参工厂化人工育苗获成功

近日,江苏省赣榆县青口镇榆城集团刺参工厂化人工育苗获得成功,填补了江苏省刺参工厂化人工育苗的空白。目前,青口镇拥有刺参育苗水体3万米3,年销售额可达1700多万元。2009年以来,榆城集团与连云港市海洋与渔业局,赣榆县海洋与渔业局共同承担了刺参工厂化人工育苗项目。为引导好这一产业的发展,科研人员从苗种、水质和管理三大方面加大管理力度,严格加强海参关键技术和新模式研发,健全海参养殖病害防治体系。     

棘皮动物的免疫防御机制

近年来,棘皮动物养殖业得到了迅速发展,尤其是海胆、海参这两个商业品种,不仅满足了国内消费者的需要,还出口国外。但是随着棘皮动物养殖快速发展,人工育苗规模不断扩大,病害问题频繁发生造成巨大的经济损失,如海参的烂皮病、海胆的黑嘴病等,在一定程度上阻碍了养殖业的健康稳定发展。     

海参养殖之二海参养殖中存在的问题及其对策

近年来,沿海地区海参养殖业蓬勃发展,但随着养殖规模的不断扩大,海参养殖中存在的问题日益凸现。从2004年水产养殖病害测报中可以看出,海参病害以2月份~4月份最为严重,7月份~9月份趋于平缓,进入12月份以来又有爆发迹象。海参病害的发生对海参养殖业产生了一定冲击,影响了海参养殖业健康、有序的发展。笔者结合生产实际谈以下几点看法:一、海参养殖中存在的问题1.苗种问题全人工育苗成功解决了海参养殖的苗种数量问题,但随之而来的苗种质量问题一直困扰着广大养殖者。育苗生产不规范,造成苗种质量下降,直接影响了海参养殖生产的全过程。2.环…     

南方工厂化鲍参混养试验

正红刺参具有生长速度较快、抗病能力强、较耐高温、体壁厚、胶原蛋白、粘多糖等营养物质丰富等特点,经济价值为刺参的2~3倍。随着红刺参繁殖驯化的成功,成功打破了海参增养殖的海区限制,将海参增养殖海域扩展到南方海域,利用南方冬春季进行海参养殖能有效避免海参冬眠现象,缩短了海参的生长周期。另一方面,由于近年来鲍鱼养殖业的畸形扩张导致了鲍鱼养殖业饱受病害困扰,养殖成功率急剧下降,工厂化养殖更甚,如何优化     

昌黎县海湾扇贝养殖信息采集与分析

<正>昌黎县拥有64.9km海岸线,浅海及滩涂资源丰富。近年来,昌黎县以渔业增效、渔民增收为核心,以养殖结构调整为主线,进一步实现由规模渔业向生态效益渔业、由传统渔业向现代渔业的转变,重点发展了浅海筏式扇贝养殖、滩涂养殖、工厂化养殖和人工渔礁养殖等,特色水产品有扇贝、海参、对虾、河鲀、牙鲆、大菱鲆、半滑舌鳎等。随着浅海养殖业的兴起,水产品加工、育苗、销售     

海参饲料研究的现状与发展方向

自20世纪80年代以来,随着海参人工育苗与养殖产业的迅速发展,海参用饲料研究越来越受到业内人士的关注。海参用饲料的好坏,直接影响海参育苗与养殖生产的成败。特别在目前,苗种生产与成参养殖迅速发展,海参用饲料需求量不断增加,而原料又十分短缺、饲料市场比较混乱,海参饲料开始成为限制海参苗种与养殖生产业发展的潜在因素。为此,笔者将综合叙述海参用饲料研究的发展过程、现状,并探讨其存在的问题以及今后发展的方向,供广大从事海参研究、教学、生产者参考。1海参用饲料的发展过程1.1国外海参饲料的研究工作始于刺参人工育苗方面的研究,…     

Association between the interannual variation in the oceanic environment and catch rates of bigeye tuna (Thunnus obesus) in the Atlantic Ocean

The environmental processes associated with variability in the catch rates of bigeye tuna in the Atlantic Ocean are largely unexplored. This study used generalized additive models (GAMs) fitted to Taiwanese longline fishery data from 1990 to 2009 and investigated the association between environmental variables and catch rates to identify the processes influencing bigeye tuna distribution in the Atlantic Ocean. The present findings reveal that the year (temporal factor), latitude and longitude (spatial factors), and major regular longline target species of albacore catches are significant for the standardization of bigeye tuna catch rates in the Atlantic Ocean. The standardized catch rates and distribution of bigeye tuna were found to be related to environmental and climatic variation. The model selection processes showed that the selected GAMs explained 70% of the cumulative deviance in the entire Atlantic Ocean. Regarding environmental factors, the depth of the 20 degree isotherm (D20) substantially contributed to the explained deviance; other important factors were sea surface temperature (SST) and sea surface height deviation (SSHD). The potential fishing grounds were observed with SSTs of 22–28°C, a D20 shallower than 150 m and negative SSHDs in the Atlantic Ocean. The higher predicted catch rates were increased in the positive northern tropical Atlantic and negative North Atlantic Oscillation events with a higher SST and shallow D20, suggesting that climatic oscillations affect the population abundance and distribution of bigeye tuna.     

Rare serotype occurrence and PFGE genotypic diversity of Streptococcus agalactiae isolated from tilapia in China

Previously, we reported 10 PEGE types of 85 tilapia Streptococcus agalactiae(GBS), which shifted from Streptococcus iniae in China, by using PEGE method. Presently, larger and more representative tilapia GBS were isolated, for the ?rst time in China, to characterize their serotypes and genetic diversities more precisely than had done before. 168 GBS strains were distributed in ?ve provinces of China, in which Guangdong, Guangxi and Hainan were the major ones, holding36.9%(62/168), 37.5%(63/168) and 19.6%(33/168), respectively. Serotypes, Ia, Ib and III, were observed in these strains and the most predominant one was Ia(95.2%), which mainly distributed in Guangdong, Guangxi and Hainan. Ia initially occurred in 2009, it shoot up to 32.1% in 2010,but decreased to 16.1% in 2011 before went up to 45.2% in 2012. Ib sporadically occurred during2007–2011, III onlyoccurred in 2012. 14 different PFGE types, including 4 new types(N, O,P and Q), were observed, in which B, D, F and G were the predominant types, holding 83.9%(141/168) of the total GBS strains. Ia corresponded to 11 PFGE types(A–H, N–P), in which type D predominated(51%). Ib represented 3 genotypes(I, J and Q) and III harbored only 2genotypes(N and F). Type N and Fsynchronously presented in Ia and III. In summary, the genetic diversity of tilapia GBS varied by serotypes and changed with geographical locations and years.Although Iastillpredominated, new rareserotypeIII alreadyoccurred in China.     

Evaluation of a Fast Method Based on the Presence of Two Restriction Sites in the Mitochondrial ND5 (mt ND5) Gene for the Identification of Scomber Species

The purpose of this work was to evaluate the suitability of a method based on the presence of two restriction sites (for Hae III and Hindf I) in the mitochondrial NADH dehydrogenase subunit 5 (mt ND5) gene to identify Scomber species. The evaluation was performed on 144 reference and market samples by sequencing of the entire 505-bp fragment of the mt ND5 gene and of a 464-bp fragment of the Kocher fragment of the cytochrome b gene (mt Cytb). Sequence analysis of any of the two fragments allows the identification of each of the four Scomber species, but S. japonicus and S. colias had the same restriction sites at the ND5 amplicon and would not have been differentiated by this analysis. Similarly, loss of the Hae III site in some S. scombrus individuals would have misidentified them as not being Scomber. All the market products were correctly labeled except one acquired in Spain labeled as originating in the Atlantic and containing S. japonicus.     

Growth performance,digestive enzyme activity and immune response of Japanese sea bass,Lateolabrax japonicus fed with fructooligosaccharide

In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.     

Purification and partial characterization of GtHs (cfLH and cfFSH) from Indian walking catfish (Clarias batrachus) (L.) and development of a homologous ELISA for cfLH

Two gonadotropins (GtH; Qa and Qb) were purified by gel filtration and ion exchange chromatography from the pituitaries of Indian walking catfish (Clarias batrachus). The presence of GtH during purification was assessed by in vitro oocyte maturation and in vivo steroidogenic activity, and their identities were determined by elution profiles, molecular weight, biological activities and yield. The molecular weights of Qa and Qb were 37 and 42 kDa, respectively, and composed of distinct subunits (Qa: 20 and 14 kDa and Qb: 26 and 18 kDa). Polyclonal antibodies raised against Qa immunostained Qa, Qb and pituitary GtH cells. A competitive Qa‐ELISA was developed whose sensitivity was 6.25 ng mL^?1 (1.25 ng well^?1) with intra‐ (3.5%) and inter‐ (12.4%) assay coefficients of variation. Displacement curves parallel to the standard were obtained with plasma and pituitary extracts of catfish, Qb and carp GtHII. The assay was validated by measuring the plasma Qa levels after LHRH treatment and in relation to ovarian growth in the female catfish during different reproductive phases. Based on the results, Qa and Qb corresponded to fish LH and FSH respectively. The findings will increase the knowledge of the mechanisms controlling fish reproduction and identification of sensitive phases in fish in captivity for hormonal manipulation.     

Controlled infection of Poecilia reticulata Peters (guppy) with Tetrahymena by immersion and intraperitoneal injection

Tetrahymena is a protozoan parasite, which infects guppy, Poecilia reticulata Peters, and causes substantial economical losses in commercial farms worldwide. Studies of guppy infected by Tetrahymena require standardized infection protocols. The LD50 for Tetrahymena infection of guppies by intraperitoneal (IP) injection was calibrated, and the level obtained was 946 parasites per fish. Guppy infection with Tetrahymena by immersion, imitating the natural route of infection via the integument, was studied under normal or stress conditions. Exposure to cold and netting (CNI) and to cold only (CI) followed by immersion exposure to 10 000 Tetrahymena per mL resulted in 22.5% and 19.2% mortality, respectively, as compared to 14.2% and 10% in groups that were netted only (NI) or non‐stressed (I). Histopathology revealed that immersion infection resulted in a systemic infection. Lysozyme levels, measured 3 weeks after infection, were significantly higher in the CNI group (288 μg per mg protein) compared with CI‐, NI‐ and I‐treated groups (94.5, 64 and 62.3 μg mg^?1, respectively). There was no evident parasite immobilization activity in body homogenates, suggesting no development of acquired immunity. Re‐infection by IP injection revealed no increase in protection in any of the treatment groups, mortality range of 56.3–75%, higher than in the non‐exposed control (40.6% mortality).     

The optimal dietary protein level of juvenile silver sillago Sillago sihama at three dietary lipid levels

A 5 × 3 factorial growth trial was conducted to evaluate optimal dietary protein and lipid levels (dietary protein level, DP; dietary lipid level, DL) for juvenile Sillago sihama (S. sihama) (2.0 ± 0.02 g, initial weight). Fish were fed 15 diets containing 5 DPs (350, 400, 450, 500 and 550 g/kg) and 3 DLs (60, 90 and 120 g/kg) for 8 weeks. The interaction between proteins and lipids significantly influenced the feed conversion ratio, condition factor, body composition, antioxidant indices and lipase activity (p < .05). DP 450 g/kg showed the highest average final body weight. DPs 500 and 550 g/kg significantly decreased the protein efficiency ratio (p < .05). DL 120 g/kg showed the highest percentage weight gain. The low feed conversion ratio was found in diets P45L12, P55L9 and P55L12. Diet P45L12 showed high superoxide dismutase activities. DP 450 g/kg showed the lowest average malondialdehyde content. Lipase activity was increased by increasing DP (p < .05) with a fall at DP 550 g/kg. Under the present experimental conditions, the optimal DP for S. sihama was 450 g/kg under the DL 120 g/kg.     

Vitamin D3 and the renal handling of phosphate in American eels

Cholecalciferol (Vitamin D₃) increased plasma inorganic phosphate concentration in American eels,Anguilla rostrata, in a dose-dependent fashion. This response was more marked in phosphate loaded fish. In control as well as phosphate loaded eels the hyperphosphatemic response to D₃ was associated with a sharp reduction in renal phosphate clearance relative to¹⁴C-polyethelene glycol (PEG) clearance. Glomerular filtration and urine flow rates were not affected by D₃. As renal phosphate clearance, even in phosphate loaded eels, never significantly exceeded that of PEG, it is suggested that D₃ reduced the relative clearance rate of phosphate by increasing renal phosphate reabsorption rather than by reducing the tubular secretion of phosphate.