衡水湖渔业经济与水环境

渔业活动对水环境的危害,使渔业经济受到制约,但渔业经济的重要地位不可忽视。以衡水湖为例,寻求湖泊渔业经济与水环境关系平衡,探索促进水环境改善前提下发展渔业经济的可行性策略和方法。     

规模化,成为溧阳生态养殖亮点

本刊讯":生态立市"是江苏溧阳市经济与社会战略发展方针的一部分,其中着力推进的水产业生态养殖规模化,就是该市经济与环境发展的一大亮点。水产经济,历来就是江苏溧阳市众多经济成分中的一个支柱产业。近年来,溧阳市通过多种政策措施,上下动     

渔村经济与管理

渔村是渔业生产的基地,研究渔村经济的发展运行问题是渔业经济研究工作的主要任务。本文作者着重讨论渔村经济基本特性,並以当前渔村经济运行中存在的主要问题为内容,探讨渔村经济管理的规律。     

我国海洋经济的发展前景及潜力上市公司介绍

20世纪90年代以来,我国海洋经济以两位数的年增长率快速发展。海洋经济的活动范围多方向扩展,经济总量迅速增加。海洋经济的增长速度快于全国国民经济增长,也快于一直处于领跑地位的沿海发达地区经济的增长,海洋产业发展速度快于行业整体产业的发展。     

我国“十三五”海洋渔业经济发展方向

海洋渔业经济是海洋经济的重要组成部分。本文围绕我国"十三五"海洋渔业经济发展方向,阐述海洋渔业经济遵循的发展理念,提出主要发展措施。     

基于灰色关联度分析的我国渔业经济产值影响因素评价

本文选取2003～2012年十年间的渔业经济产值及其影响因素的相关数据,使用灰色关联度方法进行分析,再利用层次分析法构建评判矩阵,计算各因素对渔业经济产值的影响度。分析结果表明,水产养殖、水产加工与渔业经济产值密切相关,而劳动力投入、海洋捕捞与渔业经济产值关联度最低。据此认为,应该在水产养殖、水产加工、科技引进、资源保护方面重点投入,实现渔业经济的加速发展。     

2010年全国渔业经济发展突出体现六大亮点

2010年以来,全国渔业经济经受住了国内外经济环境复杂多变的考验和频发的自然灾害的挑战,继续保持平稳较快的发展。全年渔业经济和渔业工作突出体现六大亮点:     

水产品加工行业体验营销的经济特性分析

体验经济是从服务经济中分离出来的、具有更高价值的经济形态。本文对近几年舟山新区水产品加工业体验营销的现状进行经济学上的理论分析,总结体验营销不同于传统销售方式的经济特点,要求加工企业增强体验意识,规划和设计新的适合体验的产品体系,促进现有产品加工的升级换代。     

SPSS聚类分析方法在海洋经济中的应用

通过SPSS软件对我国沿海11省(市)2011年海洋经济的面板数据进行实聚类分析,对各层次海洋经济实体发展规律进行总结并提出建议。分析结果表明,可以根据相似度将沿海地区海洋经济划分为四类:第一类是海洋经济高度发达地区,包括广东、山东省;第二类是海洋经济发达地区,包括上海市;第三类是海洋经济中等地区,包括天津市和辽宁、江苏、浙江、福建省;第四类是海洋经济欠发达地区,包括河北、海南省和广西壮族自治区。从整体来看,我国海洋经济发展态势良好,产业结构调整有序进行。     

青岛市渔民专业合作社发展探究

<正>所谓渔业合作经济组织,就是渔民在不改变渔区经营制度的基础上,按照自愿联合、经济参与、共同所有、民主管理的原则联合组建而成,从事同业产品经营及其社会化服务并具备法人资格的合作经济组织。目前其基本类型一般分为3种,即股份合作制经济、专业合     

几种添加剂对红鳍东方的促生长效果与RNA/DNA关系

在饲料中加入5种添加剂饲喂红鳍东方Tun32d，测定鱼体增重率为RNA、DNA含量，结果表明，5组饲料的增重率分别为106．96％、82．92％、83．46％、102．94％、83．23％，对照组为78．09％；RNA／DNA分别为4．47、2．56、2．72、4．21、2．65，对照组为2．35。增重率为RNA／DNA呈线性关系。试验表明，肌肉中RNA／DNA比率是一个非常灵敏地反映鱼类生长的指标，可作为鱼类生长及其饲料添加剂优劣的指标。     

短期禁食改善池塘养殖草鱼的食用品质

为探讨短期禁食提升池塘养殖鱼类食用品质的技术可行性，以3个邻近池塘养殖的商品草鱼为对象，分别转移至另一个池塘的3个网箱中，进行21 d短期禁食。每间隔7 d采集3个池塘来源的草鱼，并将鱼体分割为A、B、C、D共4个身段，采集其肌肉样品，对肌肉水分、粗蛋白质、粗脂肪和糖原含量进行定量分析。结果显示，禁食7 d时，不同身段肌肉营养物质含量即发生改变，14 d时粗蛋白含量和粗脂肪含量变化较大，其中尾部(C、D段)的粗蛋白含量有显著增加的趋势；而10号池塘来源的草鱼A段粗脂肪含量在14和21 d分别比0 d减少了22.60%和17.07%,B、D段分别在7、14和21 d比0 d减少了7.50%、19.41%、12.61%和28.83%、36.68%、13.49%,17号池塘来源的的草鱼A、C和D段在7 d后显著增加，B段在7、14和21 d比0 d分别减少了26.76%、58.41%和62.90%,D段在7和14 d比0 d分别减少了1.52%和22.58%。3个池塘来源的草鱼肌糖原含量(C、D段)有显著增加的趋势。采集草鱼身体B段背部肌肉样品，测定其肌肉系水力、肌肉质构特性和组织切片，发现...     

Effects of dietary carbohydrate level on growth and body composition of juvenile tilapia, Oreochromis niloticus×O. aureus

A growth trial was conducted to feed juvenile tilapia (initial weight, 9.1±0.1 g), Oreochromis niloticus×O. aureus, isonitrogenous diets for 8 weeks. Six diets were formulated containing 29% crude protein from casein and gelatin, 10% crude fat from soybean oil and refined soybean lecithin and varying levels of corn starch ranging from 6% to 46% at increments of 8%, with corresponding energy to protein (E/P) ratios of 35.6, 37.9, 40.2, 42.5, 44.8 and 47.1 kJ g^?1. Weight gain (WG), specific growth rate, feed efficiency ratio and protein efficiency ratio were significantly higher in fish fed diets with starch ≥22% (or E/P ratio ≥40.2 kJ g^?1) than in fish fed diets with 6% or 14% starch (or E/P ratio of 35.6 or 37.9 kJ g^?1). No further improvement was measured when dietary starch content increased beyond 22%. Body protein retention showed the same general pattern as WG, and was highest in fish fed the 22% starch diet. Body composition was significantly affected by dietary starch level. Fish fed diets with starch ≥30% had significantly higher lipid content than fish fed diets with 6% or 14% starch. Ash content was negatively correlated with starch inclusion level, but moisture and protein contents did not show discernible trends among treatments. Results indicate that hybrid tilapia can utilize 46% dietary starch without growth retardation, while 22% starch in feed for juvenile tilapia containing 29% protein and 10% lipid, or an E/P ratio of 37.9 kJ g^?1 is optimal.     

渔业PPMs与海洋生态系统

所有捕捞活动都会对海洋生态系统造成影响。渔业PPMs作为一项有贸易影响的环境措施应运而生并普遍存在,并成为GATT/WTO下诸多贸易争端的焦点。GATT/WTO争端解决机构在大量实践中逐渐的调整着自己的态度。国际立法也对负责任渔业行为中的渔业PPMs作了很多有益规定,如渔具选用、渔业管理措施等。但是如何科学完善渔业PPMs,保护海洋生态系统仍是一项长期和复杂的任务。     

Proteolytic enzymes in fish development and the importance of dietary enzymes

The development of proteolytic enzymes (trypsin, chymotrypsin and aminopeptidase) was studied in three species of fish: Coregonus sp. (hybrids of C. wartmanni and C. lavaretus from Lake Constance), Salmo gairdneri and Rutilus rutilus. Enzyme activity increased more or less with increasing age, particularly in R. rutilus. In this species (a stomachless cyprinid), the level of proteolytic activity was considerably higher than that of S. gairdneri and Coregonus. However, in trout, the low activity of pancreatic enzymes may be compensated by the action of the stomach whereas in coregonids the stomach is not developed until 50 days (body weight without gut content: 65 mg; temperature: 10°C) after hatching. In coregonids this may lead to insufficient digestion of proteins which nevertheless can be compensated by the use of exogenous (dietary) enzymes ingested together with the natural diet. In coregonid larvae fed with Moina sp., exogenous trypsin represents a very high portion of the total tryptic activity. In juveniles older than 60 days (> 150 mg) and in the other two species, the exogenous portion of tryptic activity is less important. Furthermore, a change in the pattern of tryptic isozymes has been found during development of coregonids. It is concluded that low enzyme production as well as the absence of a stomach in the first few weeks after hatching are two important reasons for difficulties in rearing coregonids on an artificial diet.     

Controls for trout and char migratory/resident behaviour mainly in stream systems above and below waterfalls/barriers: a multidecadal and broad geographical review

Northcote TG. Controls for trout and char migratory/resident behaviour mainly in stream systems above and below waterfalls/barriers: a multidecadal and broad geographical review. Ecology of Freshwater Fish 2010: 19: 487–509. © 2010 John Wiley & Sons A/S Abstract – Controls for trout and char migratory and resident behaviour in rivers and streams for above and below natural and man‐made waterfalls/barriers are covered in a multi‐decadal (1950–2000) and wide geographical review (North America, UK, Europe, Japan) that includes reference to over 380 publications. These note 53 for rainbow trout, 61 for cutthroat trout, 104 for brown trout, 47 for bull trout, 41 for brook trout, 35 for Dolly Varden and 42 for white‐spotted char, plus a few general contributions of relevance on some. For each of these species, there has been a major increase in relevant decadal publications since the early 1980s, no doubt in large part because of the upsurge in micro‐genetic methodology for DNA and related technology, coupled with a broadening of interest in stream migratory behaviour of salmonids. Main mechanisms for the control of stream migratory versus resident behaviour appear to cover an interplay among both genetic and environmental factors; in some populations and locations, genetic controls seem to be more important than environmental ones, but in others the reverse. Habitat degradation by various human activities and their introductions of non‐native fish species are becoming causes of reduction in abundance of above and below waterfall stream populations for several of these salmonid species.     

In vitro hepatic monodeiodination of L-thyroxine and the temporal effect of 17β-estradiol on deiodination in rainbow trout (Salmo gairdneri Richardson)

Thein vitro hepatic monodeiodination of L-thyroxine (T4) to triiodo-L-thyronine (T3) in rainbow trout (Salmo gairdneri) was found to be pH- and temperature-dependent, and was related to the amount of homogenate in the reaction vessel, suggestive of an enzyme-regulated event. Dithiothreitol (DTT) introduced into the reaction medium stimulated T3 production in a dose-related manner, whilst 6n-propyl-2-thiouracil (PTU) inhibited T3 production, also in a dose-related manner. The conversion was stimulated in the presence of light and depressed at buffer concentrations of less than 0.1 M.Prior treatment of fish with an intraperitoneal slow-release implant containing 17-estradiol (E2), at doses which are known to induce chronic mild elevations in plasma E2 levels, elicited a biphasic response to E2 as regards hepatic T3 production from T4 with a depression of T4 to T3 conversion evident within 1–2 days after implantation, and a subsequent stimulation of T3 production evident 56 days after, implantation. This increased hepatic deiodinase activity after chronic exposure to E2 at physiological doses was accompanied by a 3.5 fold increase in Vmax without a significant change in Km, suggesting the presence of an increased amount of the enzyme.     

纳豆芽孢杆菌固态发酵罗非鱼下脚料过程相关参数变化及产脂肽动力学

为了探明发酵参数与脂肽生成间的关系,实验以罗非鱼下脚料为主要基质接种纳豆芽孢杆菌,控制一定条件在三角瓶中进行固态发酵,测定发酵过程中菌体量、基质的温度、pH、水分含量、生物酶活性、蛋白含量及水解度和抗菌脂肽生成量;通过数学拟合建立底物消耗、菌体生长、脂肽生成的动力学模型,并分析各参数与脂肽生成和蛋白水解间的关系及其变化规律。结果显示,在下脚料固态基质中生长曲线为典型的S型,最大生长速率μm为0.2355×10~8 cfu/h,48 h菌体处于最大生长量,通过动力学模型拟合,符合Logistic模型。脂肽的生成趋势和菌体生长基本一致。同样符合Logistic模型,最大生成量为7.30 g/kg,最大生成速率为0.1112 g/h。在菌体生长过程中,基质中的蛋白酶活性在前期呈直线上升的趋势,48 h达到最高30 304.56 U/g,随后迅速下降。在菌体生长前60 h,基质中的粗蛋白含量呈直线下降,最终水解度达26.26%,蛋白消耗动力学模型符合物料衡算理论模型。发酵过程中,基质的温度、pH和水分会发生小幅波动。研究表明,脂肽生成和菌体生长是偶联型;蛋白酶是同步合成型,蛋白酶产量可以为后续二步酶解制备小肽提供充足酶源;建立的动力学模型拟合度好,可以用于描述发酵过程和脂肽生成规律。本研究为利用罗非鱼下脚料固态发酵生产抗菌脂肽和营养小肽复合型活性肽工业化生产调控提供了重要的理论依据。     

Melatonin, but not somatostatin-14 influences in vitro steroidogenesis by ovarian follicles of rainbow trout

Ovarian follicles taken from sexually maturing rainbow trout at the mid-vitellogenic stage of ovarian development were incubated in vitro in the presence or absence of melatonin or somatostatin-14 (SRIF-14) to determine whether there is evidence of a direct action of these factors on gonadal steroidogenesis in fishes. The steroidogenic capacity of the ovarian follicles was assessed by measuring testosterone (T) and 17-estradiol (E₂) release into the incubation medium, and by examining the steroid metabolites produced following incubation of follicles with radiolabelled steroid precursors.Melatonin appears to elicit a biphasic effect on steroidogenesis by in vitro rainbow trout ovarian follicles; at a concentration of 1 × 10^–3 M, melatonin stimulated basal T and E₂ production, but at a concentration of 1 × 10^–2 M there was an inhibition of basal and sGtH-stimulated T and E₂ Melatonin may act to reduce the activity of specific steroidogenic enzymes, since there was evidence of melatonin at 1 × 10^–2 M enhancing the accumulation of [³H]17-hydroxyprogesterone in the medium following incubation with [³H]pregnenolone, possibly suggesting the inhibition of C_17,20-lyase activity. In contrast, SRIF-14, used at concentrations of 1 × 10^–8 M and 1 × 10^–6 M, had no effect on basal or sGtH-stimulated E₂ or T production by ovarian follicles, incubated in vitro.     

Soybean molasses as an organic carbon source in the farming of Litopenaeus vannamei (Boone, 1931) in a biofloc system

Soybean molasses was evaluated as a partial replacement for sugarcane molasses as a carbon source for biofloc development in the superintensive culture of Pacific white shrimp (Litopenaeus vannamei). A 50‐day study was conducted with juvenile (3.2 g) shrimp stocked in 16 800 L tanks at a stocking density of 250 shrimp m^?3. Control of total ammonia concentration was performed by the addition of combined mixtures of soybean and sugarcane molasses to the culture water. Three different molasses treatments were evaluated using different soybean‐to‐sugarcane molasses ratios: 15–85%, 38–62% and 60–40% respectively. The control group was treated only with sugarcane molasses. Water quality, chlorophyll a concentration, heterotrophic bacterial load, Vibrio spp. concentration and zootechnical indexes were all evaluated. Total ammonia concentration was controlled by heterotrophic and chemotrophic pathways. Biofloc formation, as quantified by measuring the total suspended solids, was not altered. The Vibrio spp. concentration showed a significant reduction in treatments with soybean‐to‐sugarcane molasses ratios of 38–62% and 60–40%. All combined mixtures of soybean and sugarcane molasses could maintain water quality and productivity in the superintensive culture of L. vannamei using the biofloc system. Thus, the potential use of a residue from agroindustry as a carbon source in a biofloc culture is demonstrated.