长江口水域主要渔业生物资源状况的分析

利用长江口水域20世纪90年代的拖网生产资料以及生物学测定数据,分析该水域拖网生产的渔获种类及优势种的资源变化状况。结果表明:20世纪90年代各时期长江口水域拖网生产的渔获物中,鱼类占92%以上,头足类和甲壳类所占的百分比较小,分别在8%和1%以下。每个时期的拖网生产的种类数基本相当,都为40种左右;同一时期的不同季节和各季节的不同时期间的种类数均有明显的变化。随着时间的推移,长江口水域拖网渔获物优势种类的组成发生了一定的变化。从90年代初期到末期,大部分传统优势种的渔获比例相对稳定,某些优势种的渔获比例有较大的波动或急剧减少,小型低质鱼种的渔获比例和种数增加。对带鱼、小黄鱼的体长组成结构分析表明它们的群体从20世纪80年代开始趋于明显的小型化,当前的小型化程度已经相当严重;而在此期间黄鲫的体长组成结构变化不大。该水域的优势种类组成和主要优势种类体长组成结构的变化是和逐渐增加的捕捞力量以及水域环境变化相关联的。     

几内亚渔场单拖网具渔法探讨

介绍了大连海洋渔业集团公司渔轮赴几内亚渔场作业的六片式单拖网，分析了该网具有主要技术性能和网具装配，探讨了网具调整措施。     

南海北部拖网30．3mm方形网目网囊的渔获选择性分析

根据1997年10月和2000年11月在南海北部珠江口以外传统拖网渔场进行的网目选择性试验资料,分析了网目内径为30·3mm的方形网目网囊对南海北部多种渔获的选择性能。结果表明,这种规格的方目网囊平均尾数逃逸率为29·76%,平均重量逃逸率为8·46%;出现在套网中的经济种类少、数量少,条尾绯鲤、金线鱼、多齿蛇鲻、大头狗母鱼4种鱼的尾数和重量分别占套网抽样渔获的95·4%和86·0%;网囊中带鱼、长尾大眼鲷、黄鳍马面鲀、白姑鱼、深水金线鱼等鱼种的体长小于可捕标准的个体尾数比例均超过或接近50%,枪乌贼、乌贼、乌鲳等幼鱼尾数比例达90%以上,多齿蛇鲻和金线鱼50%选择体长均未达到最低可捕标准,表明该种规格网囊对多数经济种类幼体的损害比较严重。总体来说,使用该规格的方目网囊作业不利于南海北部多数种类资源的繁殖、恢复及其可持续利用,不利于海洋生物多样性保护。     

Measuring the height of the fishing line and its effect on shrimp catch and bycatch in an ocean shrimp (Pandalus jordani) trawl

The relationship between fishing line height (FLH), shrimp catch and bycatch in a semi-pelagic ocean shrimp (Pandalus jordani) trawl was investigated using a newly developed recording inclinometer. The inclinometer was effective at measuring FLH and indicating trawl performance deficits. FLH was determined to be stable during a haul and also between hauls within a given footrope and groundline configuration. FLH was readily adjusted with simple modifications to the footrope “dropper” chains. Inclinometer data showed that FLH can be unequal between double-rigged nets of identical configuration. Shrimp catch and the bycatch of flatfish and juvenile rockfish varied inversely with FLH, suggesting FLH can be adjusted to equalize the catch of shrimp, flatfish and juvenile rockfish between two double-rigged shrimp nets.     

Performance of herbaceous Evolvulus pilosus on urban green roof in relation to substrate and irrigation

Rooftop gardening (or green roof establishment) is an urban greening afforestation method that has many environmental, economic, and urban landscaping benefits. For rooftop vegetation, stressful environments that include heat, strong winds, sunshine, and drought prevent many plants from growing well, especially in shallow soil. To establish low cost urban rooftop gardens with a low weight substrate in the summer, we evaluated the green coverage and growth of a suitable groundcover ornamental plant, blue daze (Evolvulus pilosus). Blue daze was used as rooftop vegetation in a shallow substrate (10 cm thick) on the flat rooftop of a four-story building in the middle of Kobe city, Japan, which has a temperate and humid climate. On average, the diurnal maximum temperatures and the total amounts of precipitation during each planting experiment between July and September were 30.8 °C and 247 mm in 2008 and 33.2 °C and 458 mm in 2009, respectively. Three different types of planting substrates (AS, amended soil, TM, turf mat as a dried-up blocks of sod, and FBA, furnace bottom ash) were tested to determine how they influenced plant cover, flowering, and growth. We evaluated the physical and chemical properties of the substrates that were used to establish the rooftop greeneries. In addition, the economy, ornamental and ecological values, reuse of material, and low rooftop weight burdens of the substrates were evaluated. The greatest blue daze ground cover occurred on the TM substrate (relative to the AS and FBA substrates) approximately three months after transplanting. The blue daze actively bloomed on all substrates throughout midsummer. However, alternate day irrigation largely reduced their shoot growth and flowering relative to daily irrigation. The AS and TM substrates had suitable physicochemical properties for use as planting substrates and had ideal solid, liquid, and vapor phase distributions and high water and nutrient holding capacities. FBA was a poor substrate with very low water and nutrient retention capacities, which resulted in depressed plant growth, especially under low watering conditions. To recycle FBA efficiently as a shallow low-cost planting substrate for rooftop gardening, the addition of coated fertilizers and organic matter to FBA should be considered to improve its water and nutrient holding capacities.     

On the Non-price Bottom Bidding System under the Mode of Valuation with Bill Quality of Construction Works

It is the direction of the project bidding system reform to apply the non-price bottom bidding system under the mode of valuation with bill quality of construction works in China. In this paper, the significance of implementing the non-price bottom bidding system is analyzed and emphasis is put on the workout of the non-price bottom bidding, valuation and so on. The risk prevention and risk management are studied on the side of tenderee from the qualification examination, engineering guarantee, defending system and so on.     

油罐腐蚀底板的可靠性数学模型研究

根据油罐底板的损坏形式和腐蚀特征,认为腐蚀深度的分布服从极值Ⅰ型最大值分布,腐蚀寿命服从极值Ⅰ型最小值分布。按照这一分析结论,建立了以实测数据为基础的可靠性计算模型(静态可靠性模型)、可靠性预测模型(动态可靠性模型)和给定可靠度前提下的可靠寿命计算模型。实例计算表明,该模型对于油罐的防腐工作具有重要的理论指导意义。     

光诱鱿鱼浮拖网渔具渔法试验

首先对诱鱼光场进行计算，并分析其对光诱鱿鱼浮拖网作业的影响，据此合理配置了灯光强度及其布局，探讨了一套较有效的诱导渔方法。根据鱿鱼的趋光习性及浮拖网的特点，设计了适应在较深渔场作业的光诱浮拖网渔具，并成功地试验了光诱鱿鱼浮拖网柔性网板；取得了良好的社会生态效益和经济效益。     

东海区方形目与菱形目拖网网囊对小黄鱼的选择性研究

采用套网法对双船底拖网不同网目尺寸(40、50、60、65 mm)的方形目和菱形目网囊捕捞东海区小黄鱼(Larimichthys polyactis)进行选择性实验,对不同网囊网目结构、不同网囊网目尺寸的选择性数据进行了比较分析。结果表明:(1)网囊网目尺寸小于50 mm,小黄鱼的逃逸率极低,网目结构选择性差异不明显。大于50 mm时,方形目网囊逃逸率均略高于菱形目结构,但方形目与菱形目逃逸率差异并不显著(P0.05)。(2)网目尺寸为50 mm、60 mm和65 mm时,方形目网囊的50%选择体长(L_(0.5))分别比菱形目网囊的L_(0.5)大28.5%、16.8%和7.3%,方形目网囊对于小黄鱼具有较好的选择性。(3)根据小黄鱼的50%选择体长(L_(0.5)),结合现行可捕体长标准以及不同阶段渔获物体型特征,建议菱形网目尺寸为60 mm或者方形网目尺寸为55 mm,二者具有相同的选择性和渔获率。     

吕四渔场虾桁拖网最小网目尺寸的研究

为了养护和管理海洋渔业资源,对虾桁拖网网囊网目进行了选择性试验,以期找到最适网目尺寸,为今后立法和管理提供科学依据。经试验表明,随着网囊网目的加大,50％选择体长也随之增加。当网囊网目内径分别为35mm、40mm、45mm时,哈氏仿对虾50％选择体长分别为72.73、74.61、81.43mm;葛氏长臂虾50％选择体长分别为70.42、75.60、79.45mm;脊尾白虾50％选择体长分别为88.37、92.05、97.17mm。 三种虾类的50％选择体长(L_0.5)与网囊网目内径(Me)的线性回归方程如下: 哈氏仿对虾:L_0.5=469+0.8697Me R~2=0.9029 葛氏长臂虾:L_0.5=39.063+0.9024Me R~2=0.9927 脊尾白虾:L_0.5=57.325+0.8801Me R~2=0.9911 三种虾类混合:L_0.5=37.597+1.1470Me R~2=0.9996 将网囊网目尺寸由现在的20mm到25mm提高到35～40mm,则在此网目大小下,能释放掉大量70mm以下的幼虾,而捕获的商品虾质量有明显改善。根据试验结果和分析,建议对虾桁拖网加强管理,制定相应的法规,规定最小网目尺寸。