水利工程施工期环境影响与环境对策

水利工程施工期长、施工人员多、施工机械吨位大、数量多;施工期间进行的土石方爆破、开挖、库区清基、大坝修筑、生活管理区建设等项作业,对库周环境将产生很大影响。因此,加强和完善施工期环境影响评价与环境对策的研究工作,对保护库周环境意义重大。 一、环境影响分析 水利工程施工作业将对水质、大气、噪声、地质地貌、土壤、陆生生物、水生生物、景观与文物、工区卫生等方面产生影响,如果处理不好将对     

中韩渔业协定实施后涉外渔业管理面临的问题及对策

《中韩渔业协定》实施后,由于作业海域、船数、时间、方式及渔获物配额等方面的限制,对我国的渔业管理体制产生巨大冲击,由此而引发一系列问题。     

渔船起货设备的计算负荷

本文根据我国现代海洋渔业船舶的主要尺度、作业特点、作业海况,将渔船升沉、摇摆时鱼货、渔具等对起贷设备产生的附加惯性力进行了分析、计算,并运用洛卡基斯——奇顿苏斯托米迪斯的耐波性标准系列图谱资料用微机进行计算,给出了船长 L=20～40米的渔船纵向各位置处起吊鱼货、渔具等的附加动载荷计算值。     

对应分析在福建拖网捕捞影响因素分析中的应用

采用随机抽样调查的方法在福建省选择29个拖网作业单位(样品)、11个作业因素(变量),用对应分析法对其影响因素进行分析,以判断福建拖网捕捞效率的主要影响因素以及了解作业单位(作业船)之间和作业单位与变量之间的关系。结果表明,当前影响福建拖网作业的主导因素是网具结构,其次是渔船的主机功率和作业天数。据此,建议从适当增大网口网目尺寸和网口周长、增加船舶主机功率和延长作业天数等方面入手,提高拖网作业单位捕捞效率。本文还通过分析平面变量与样品聚点图,将福建拖网作业分成4个类群,通过分析各类群与各作业生产因素的亲疏关系,进一步了解各类群的特点,可对生产单位和管理者调整拖网作业、优化生产资源配置等提供理论参考。     

上海郊区流刺网作业情况

上海郊区的流刺网作业，在长江作业的主要对象是刀鱼、凤尾鱼、鲥鱼，在沿海作业的主要对象是鲳鱼。从事流刺网作业的地区主要是崇明和宝山两县，其次是川沙、松江、上海、金山等     

发展中西太平洋金枪鱼围网的问题与对策

中西太平洋是金枪鱼围网最主要的作业海域.我国金枪鱼围网虽起步较晚,但发展较快,当前已初具规模,大都取得了较好的经济效益.拥有金枪鱼资源的太平洋岛国其资源保护力度不断增强.我国金枪鱼围网船都是引进的二手船,在船只的保养、使用及船员的配置、管理等方面产生了许多问题,这些问题影响作业生产,并对远洋渔业公司的收益和长远发展不利,文章就新形势下生产、管理中出现的问题进行了分析,并就如何进一步提高产量,科学管理提出了建议,以期使我国的金枪鱼围网渔业更好地发展.     

福建海区渔业资源利用现状浅析

本文主要根据1996~2004年福建海区历次渔业资源专题调查和渔业资源动态监测资料,以及1990~2003年福建省渔业统计年鉴数据资料,分析研究福建海区拖网、张网、流剌网、灯光围网等主要作业对渔业资源的开发利用状况和存在问题。结果表明拖网、张网等作业对近海渔业资源利用强度尚未有效遏制,资源结构朝着越来越不利于人们利用的方向发展。并提出控制海区捕捞强度、调整捕捞作业结构、加强福建海区主要作业生产动态监测力度、加快人工鱼礁建设和增殖放流的步伐等渔业资源管理、养护和增殖措施。     

基于北斗船位数据的江苏渔船航次分析

北斗船舶监控系统(VMS)包含渔船的位置、航速等数据,能用于挖掘渔船作业的动态信息。利用VMS数据对江苏渔船的航次和平均离岸距离进行提取,分析不同船长、类型、作业期、地区等条件下航次和平均离岸距离的特点。结果显示:1)江苏不同作业类型渔船航次差别明显,刺网航次数量最多,占总航次数的84.6%,围网和张网作业渔船的平均离岸距离和平均作业时间大于其他作业类型,围网作业渔船最远可达174.02 km;2)江苏渔船大部分为中小型渔船,作业的平均离岸距离比较小,基本在80 km以内,平均离岸距离随着吨位和功率的增大而线性增大;3)全年的航次数量变化分布整体中间低两边高,4月、9~11月航次数较多,2月、5~7月航次数较少;4)江苏不同区县渔业差距较大,航次数最多的为南通启东市、如东县和盐城射阳县,渔船作业平均离岸距离最远的为苏州太仓市,最远可达332.38 km。研究结果可为江苏省渔业管理提供参考依据。     

江苏禁止水冲式耙网作业

一段时间以来，一种名叫水冲式耙网的网具，正对江苏省沿海滩涂贝类等海洋水产资源 的生存、繁育构成巨大威胁。日前江苏省海洋与水产局作出《关于同意禁止水冲式耙网作业 的批复》，要求全省各级海洋海业主管部门下决心坚决取缔这种禁用网具及作业方式。 水冲式耙网作业，是通过附设在托梁、托条上的两台潜水泵产生高压水流冲翻滩涂底沙 ，再通过耙下部铲刀将冲起的贝类刮铲进网中。这种作业方式能一网捕尽滩涂中的大小贝类 ，既严重破坏了海底底质的生态环境，又对海洋贝类的生存、繁衍构成巨大威胁。受利益的 驱动，水冲式耙网作业自去年…     

舟山桁杆拖网渔具渔法分析

桁杆拖虾是20世纪80年代以后迅速发展起来的新兴捕捞作业方式,主要用于开发沿海渔场虾类资源.桁杆拖虾作业方式引进舟山后,迅速成为舟山海洋捕捞业的主要作业方式之一.2013年5-11月通过实地调查,对舟山地区桁杆拖网的捕捞对象、渔具结构、操作方法等进行了分析研究,指出当前舟山桁杆拖虾作业中存在的问题:底杂鱼及蟹类等副渔获物所占比例大,数量和重量占总渔获12.12％和66.58％;使用电脉冲惊虾仪等违法作业仍然存在;网目规格普遍小于国家标准.根据上述问题提出:加装分隔网片,改善网目结构,加大执法力度等相应建议.     

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.     

Protein and amino acid composition from the mantle of juvenile O ctopus vulgaris exposed to prolonged starvation

Protein and amino acid composition of the mantle of juvenile O ctopus vulgaris (Cuvier, 1797) during fasting for 27 days were determined. Average protein content of octopus mantle was of 711.19 ± 46.80 g kg^?1 DW, and it decreased with increasing fasting days. The non‐essential amino acids content was higher (486.18 ± 11.08 g kg^?1 protein) than essential amino acids (425.82 ± 9.15 g kg^?1 protein) at the start of the experiment (unstarved animals). The results suggest that the amino acid profile of the mantle where the most abundant amino acids are Arg, His, Lys, Gly, Leu and Pro could indicate a prolonged fasting condition (>20 days) or poor nutrition of O . vulgaris. This study supports the idea of using mantle for metabolic needs of starved O . vulgaris suggesting that the degradation pathway of amino acids to pyruvate and tricarboxylic acid cycle intermediates was favoured contrary to the degradation pathway of ketogenic amino acids. Special considerations should be taken concerning Thr, Ile, Ser, Ala, Asx (Asp, Asn), Glx (Glu, Gln) (because of their fast intake) and Lys and His (due to their stable contents) during a prolonged period of fasting.     

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.     

美人鱼发光杆菌对凡纳滨对虾非特异性 免疫功能及抗病力的影响

在基础饲料中分别添加0.1%和1%美人鱼发光杆菌灭活菌、0.1%美人鱼发光杆菌活菌配制成3种免疫实验饲料,以基础饲料为空白对照组饲料,每组设3个平行样。对个体质量为(4.83±0.36)g的凡纳滨对虾进行为期20 d的饲养实验,分别在0、5、10、15和20d进行取样,以血清中的酚氧化酶(PO)、酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和溶菌酶(UL)活性为免疫指标,探讨了美人鱼发光杆菌作为免疫制剂对凡纳滨对虾非特异性免疫效应的影响;在投喂免疫饲料后的第22天,按0.004 2 kg/kg体重的剂量,直接投喂对虾白斑综合征病毒(WSSV)病料,并记录累积死亡率。结果表明,美人鱼发光杆菌免疫实验组对凡纳滨对虾血清中PO、ACP、AKP、UL和SOD活性影响明显高于对照组,并且在饲料中添加美人鱼发光杆菌后,明显提高了对虾抵御WSSV感染的能力。其中0.1%美人鱼发光杆菌活菌实验组的抗病毒感染能力最强,WSSV感染14d内累计死亡率为63.3%±5.8%;而对照组为96.7%±3.3%。研究表明,美人鱼发光杆菌添加在对虾饲料中能提高凡纳滨对虾非特异性免疫水平,增强抵抗疾病的能力,将其作为对虾免疫增强剂具有良好的应用前景。     

Effects of Spirulina platensis as a feed additive on growth and coloration of blue dolphin cichlids (Cyrtocara moorii Boulunger, 1902)

This study was carried out to investigate the effects of replacing fish meal with dietary Spirulina as a feed supplement on the growth performance and coloration of blue dolphin cichlids (Cyrtocara moorii). Five isonitrogenous (47% crude protein) and isocaloric (17.36 kJ/g digestible energy) diets were for formulated to replace FM with 0, 5, 10, 15 and 20% Spirulina (designated as Control, SP5, SP10, SP15 and SP20 respectively) and fed to the fish (initial body weight, 3.15 ± 0.01 g). Fish were randomly distributed into fifteen 120 L aquariums (26.5 ± 1.00°C), 15 fish per aquarium. The diets were tested in triplicate for 12 weeks. Experimental groups were fed twice daily (09:00 and 17:00) by hand to satiation. At the end of the feeding trial, significantly (p < 0.05) higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER) and lower feed conversion ratio (FCR) were observed in fish fed the SP10 diet when compared to the SP20 diet. There was no significant difference in these parameters between the other groups. The skin coloration of blue dolphin cichlid fed a diet containing Spirulina meal was enhanced. The best coloration was observed in the SP15 group. These impressions were objectively validated by chemical determinations of carotenoids extracted from fish skins and passed statistical tests of significance. The study findings show that Spirulina meal does not diminish growth rates except at very high levels.     

Dietary thiamin and pyridoxine requirements of fingerling Indian major carp,Cirrhinus mrigala (Hamilton)

Two experiments were conducted to quantify the dietary thiamin (experiment I) and pyridoxine (experiment II) requirements of fingerling Cirrhinus mrigala for 16 weeks. In experiment I, dietary thiamin requirement was determined by feeding seven casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) with graded levels of thiamin (0, 0.5, 1, 2, 4, 8 and 16 mg kg^?1 diet) to triplicate groups of fish (6.15 ± 0.37 cm; 1.89 ± 0.12 g). Fish fed diet with 2 mg kg^?1 thiamin had highest specific growth rate (SGR), protein retention (PR), RNA/DNA ratio, haemoglobin (Hb), haematocrit (Hct), RBCs and best feed conversion ratio (FCR). However, highest liver thiamin concentration was recorded in fish fed 4 mg thiamin kg^?1 diet. Broken‐line analysis of SGR, PR and liver thiamin concentrations exhibited the thiamin requirement in the range of 1.79–3.34 mg kg^?1 diet (0.096–0.179 μg thiamin kJ^?1 gross energy). In experiment II, six casein–gelatin‐based diets (400 g kg^?1 CP; 18.69 kJ g^?1 GE) containing graded levels of pyridoxine (0, 2, 4, 6, 8 and 10 mg kg^?1 diet) were fed to triplicate groups of fish (6.35 ± 0.37 cm; 1.97 ± 0.12 g). Fish fed diet containing 6 mg kg^?1 pyridoxine showed best SGR, FCR, PR, RNA/DNA ratio, Hb, Hct and RBCs, whereas maximum liver pyridoxine concentration was recorded in fish fed 8 mg kg^?1 dietary pyridoxine. Broken‐line analysis of SGR, PR and liver pyridoxine concentrations reflected the pyridoxine requirement from 5.63 to 8.61 mg kg^?1 diet. Data generated during this study would be useful in formulating thiamin‐ and pyridoxine‐balanced feeds for the intensive culture of this fish.     

Sea bream culture in Egypt; status, constraints and potential

Marine fish farming in Egypt began in 1976 with the culture of gilthead sea bream, (Sparus aurata) as this fish was notably adaptable to brackish and marine pond conditions. Today, marine fish and shrimp farms amount to about 19,000 ha, out of which 42% is already in production while the rest, i.e., 58% is still under construction. In 1997, cultured gilthead sea bream production of 2,250 tons made up 3% of the 75,000 tons total aquaculture catch. In polyculture, usually with the grey mullet and sea bass, gilthead sea bream contributed 440 kg ha^–1 to the total yield of 1,700 kg ha^–1 (26%) over a period of 16 months. For the same period, the yield of monoculture ponds averaged 100 kg ha^–1, while in marine cages, yields ranged from 4–10 kg m³. In 1996–1997, fry of 0.25–1 g and fingerlings 1–10 g with a total of 3 million, were collected from the wild and 1 million fry were produced in the three marine hatcheries out of the four existing ones. The development of sea bream culture in Egypt is now severely inhibited by the shortage of seeds and adequate feeds. Exports of both sea bream and sea bass, during 1994–1996 averaged 1,300 tons per year.     

A Minchinia mercenariae‐like parasite infects cockles Cerastoderma edule in Galicia (NW Spain)

The cockle Cerastoderma edule fishery has traditionally been the most important shellfish species in terms of biomass in Galicia (NW Spain). In the course of a survey of the histopathological conditions affecting this species in the Ria of Arousa, a haplosporidan parasite that had not been observed in Galicia was detected in one of the most productive cockle beds of Galicia. Uni‐ and binucleate cells and multinucleate plasmodia were observed in the connective tissue mainly in the digestive area, gills and gonad. The parasite showed low prevalence, and it was not associated with abnormal cockle mortality. Molecular identification showed that this parasite was closely related to the haplosporidan Minchinia mercenariae that had been reported infecting hard clams Mercenaria mercenaria from the Atlantic coast of the United States. The molecular characterization of its SSU rDNA region allowed obtaining a fragment of 1,796 bp showing 98% homology with M. mercenariae parasite. Phylogenetic analysis supported this identification as this parasite was clustered in the same clade as M. mercenariae from the United States and other M. mercenariae‐like sequences from the UK, with bootstrap value of 99%. The occurrence of M. mercenariae‐like parasites infecting molluscs outside the United States is confirmed.     

Involvement of gonadal steroids in final oocyte maturation of white perch (Morone americana) and white bass (M. chrysops): in vivo and in vitro studies

Plasma estradiol-17 (E₂), testosterone (T), 17,20-dihydroxy-4-pregnen-3-one (DHP) and 17,20,21-tri-hydroxy-4-pregnen-3-one (20-S) levels were measured by radioimmunoassay (RIA) in white perch (Morone americana) and white bass (M. chrysops) that were induced to undergo final oocyte maturation (FOM) with human chorionic gonadotropin (hCG). Plasma DHP levels increased in females of both species in association with oocyte germinal vesicle migration (GVM) and germinal vesicle breakdown (GVBD) and decreased thereafter. Plasma 20-S levels also increased with oocyte GVM in white bass, but were several-fold lower than DHP levels. Circulating E₂ and T levels were greatest during GVM and GVBD in both species and decreased to low levels during oocyte hydration and ovulation. Follicles from white perch and white bass which received a priming injection of hCG in vivo, produced both DHP and 20-S in vitro after exposure to hCG and their oocytes underwent GVBD. Ovarian incubates from unprimed fish of either species produced only E₂ and T and their oocytes did not complete GVBD. Oocytes from unprimed bass, but not perch, matured when follicles were exposed to hCG in vitro. Both trilostane and cycloheximide blocked in vitro production of DHP and 20-S and oocyte GVBD by white perch follices. DHP and 20-S were equipotent inducers of FOM in the GVBD bioassay. None of several other structurally-related steroids tested were effective within a physiological range of concentrations. These results indicate a role for DHP and 20-S in the control of FOM in white perch and white bass.