改性渔用乙纶单丝试验研究

以HDPE树脂、VERSIFYTM 6002弹性体合格品、松节油助剂等为原料采用特殊纺丝工艺生产出改性渔用乙纶单丝,并将其与普通渔用乙纶单丝进行拉伸力学性能比较分析.结果表明:改性渔用乙纶单丝比普通渔用乙纶单丝断裂强度提高13.1%,结节强度提高3.6%,结强损失率提高15.7%,断裂伸长率降低34.0%.改性渔用乙纶单丝结强损失率稍高和断裂伸长率较低的不足在渔业实际应用中均可以通过强度优势进行弥补.改性渔用乙纶单丝在渔业生产上推广应用具有可行性.     

渔用自增强聚乙烯和普通聚乙烯单丝耐磨性的比较研究

在对渔用自增强聚乙烯(Self—reinforced Polyethylene,简称SRPE)和普通聚乙烯(PE)单丝拉伸力学性能和内部结构研究的基础上,进行了4种单丝耐磨性比较研究。结果表明,SRPE单丝强度提高,内部结构更为完善,耐磨性增强;千摩擦和水润滑条件下SRPE单丝较PE单丝具有较高的耐磨度和断裂强度保持率;而PE单丝较SRPE单丝具有较大的断裂伸长率变化。     

网箱养鲤中适宜投饲率的研究

１９９２年１９９３两年用粗蛋白含量２２－４２％的４种配合饲料、７种投饲率（３、４、５、６、７、８、９％）进行网箱养鲤时，５、６、７、８、９月的适宜投饲率分别为５－６％、７％、７．５％、６％和５％。在饲料粗蛋白含量为２０－４０％范围内，蛋白含量增减５％，投饲率应相应减增１％。     

“旗鱼牌”、“泰渔牌”乙纶单丝荣获国家银质奖

8月31日,在北京举行的全国第七次质量月授奖大会上,上海绳网厂"旗鱼牌"、泰州渔网厂"泰渔牌"渔用乙纶单丝荣获1984年国家银质奖,党和国家领导人在大会上发了奖。获奖的这两个产品,都是今年5月农牧渔业部水产局组织全国水产系统渔用乙纶单丝质量评比中,评出的优质产品。     

抗风浪网箱材料性能的研究

报道了抗风浪网箱材料的选择、材料性能和测试结果。试验表明,开发的网箱框架高密度聚乙烯管材性能优良,其抗屈服应力达23MPa,断裂伸长率达525％～763％,纵向回缩率仅为0．3％。采用的六边形锦纶网衣网片纵向断裂强度为315～342daN,比进口挪威网衣强度高1．9％～10．7％。     

渔用纳米蒙脱土改性聚乳酸单丝降解性能

为研究纳米蒙脱土(nano-MMT)改性聚乳酸(PLA)单丝在海水环境中的降解特性,试验测试了纯PLA单丝、0.5wt%、1.0wt%nano-MMT/PLA单丝在浙江舟山海域海水中15个月的降解特性。结果显示,纳米蒙脱土改性聚乳酸单丝在海水环境中自然降解9个月时间内,其力学性能和数均分子量下降较为缓慢;当降解时间超过9个月后,改性聚乳酸单丝的断裂强度和数均分子量呈加速下降趋势。表明改性聚乳酸单丝在海水中降解9个月后进入加速降解阶段,推断改性聚乳酸单丝在海水环境中的最佳使用寿命为9个月。加入nano-MMT后,改性聚乳酸单丝力学性能和数均分子量下降较纯聚乳酸单丝要快。在海水中降解15个月后,加入0.5wt%nano-MMT的改性聚乳酸单丝断裂强度和数均分子量分别下降了25.0%和50.0%,而纯的聚乳酸单丝则仅下降了20.4%和30.6%。由于nano-MMT的加入,会使PLA与nano-MMT的界面结合产生缺陷,nano-MMT与聚乳酸大分子链之间的界面结合缺陷会成为水分子进入聚乳酸大分子内部的通道,从而加速改性PLA单丝在海水环境中的降解。同时nano-MMT的加入会加快改性PLA单丝耐磨性的下降趋势,纯PLA单丝在海水中降解15个月后,耐磨度由2.20 F/tex下降为1.32 F/tex,耐磨度下降40%;而0.5wt%nanoMMT/PLA的耐磨度由2.34 F/tex下降为0.70 F/tex,耐磨度下降70.1%。     

渔用共混改性MMWPE/PP单丝和普通PE单丝拉伸力学性能的比较

在实验室对渔用共混改性中高分子量聚乙烯/聚丙烯单丝(简称共混改性MMWPE/PP单丝)和普通聚乙烯单丝(简称普通PE单丝)拉伸力学性能进行了比较试验。结果表明,共混改性MMWPE/PP单丝较普通PE单丝断裂强度提高32.3%、结节强度提高25.6%、结强损失率提高7.4%,而断裂伸长率降低47.9%。在保持断裂强力优势的前提下,以共混改性MMWPE/PP绳网替代普通PE绳网,能使远洋拖网与养殖网具用原材料降低消耗及水阻力减小,从而实现渔业生产的降耗减阻。结论可为高性能材料的选配、远洋拖网与养殖网具的优化设计提供参考。     

着色锦纶6单丝在三层流刺网上的应用试验

近年来，随着海洋集群性经济鱼类的波动，刺网作业得到迅速发展，其产量与产值在整个海洋捕耢业中所占的比例日趋增加。锦纶6单丝是刺网的主要材料，其性能的优劣直接影响到刺网的渔获效果。近年来，人们不仅重视锦纶6单丝的物理机械性能的研究，而且对锦纶6单丝的色泽与渔获性能的关系越来越关注。鉴此，东海水产研究所已经多次试验，于1988年6月试制成原液着色锦纶6单丝——绿色着色丝、蓝色着色丝。1988-1990年全国有五省一市的10多个单位参加了着色丝海上捕耢对比试验。1991年我省泉州的鲤城区、漳州的漳浦县、闵中的平潭县三个单位率先投入着色丝在海洋捕捞渔业上的应用试验，从作业而论，着色三层流刺网海上捕捞对比试验尚属首次。本文就泉州市鲤城区进行着色锦纶6单茎在三层流刺网上的应用试验情况报告如下。     

温杖子水库网箱养殖罗非鱼试验

放养量４．５－６ｋｇ／ｍ＾３，饲养期约１００天，单产２７．０－３２．６ｋｇ／ｍ＾３，饵料系数１．３－１．７５，成本利润率５６．９％－７５．２％，能量转换率１７．９％－２３．９％。试验表明在我国北方网箱养非鱼能取得较高的经济效益。     

长吻Wei的营养和饲料研究Ⅰ水库网箱适宜投喂率

水库小体积网箱试养证明，长吻Ｗｅｉ鱼种适于网箱养殖和水库生态环境，而且生长快、饲料系数低、成活率高。长吻Ｗｅｉ鱼种经４５天饲养，由始均重６．９７ｇ长至２０ｇ以上，相对增重率达２８８％左右，成活率高达９７％－１００％。投喂率与水温关系密切。随投喂率增大，长吻Ｗｅｉ生长加快，但饲料系数逐渐增大。当水温为２６－３０℃时，适宜投喂率为４％，水温为２１－２６℃时，适宜投喂率为２％。     

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.     

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.     

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 hormone (GH) and reproduction: a review

Interaction between growth and reproduction occurs in many vertebrates and is particularly obvious at certain stages of the life cycle in fish. Endocrine interactions between the gonadotropic axis and the somatotropic axis are described, the potential role of GH being emphasised. A comparative analysis of these phenomena in mammals, amphibians and fish, suggests a specific role of GH in the physiology of puberty, gametogenesis and fertility. It also shows the original contribution made by studies on the fish model in this field of investigations.     

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).