海洋网箱网衣无公害防污技术的初步研究

根据不同的防污机理,采用内填充及涂敷方法,制备了几种不同种类的防污网衣材料,包括添加纳米无机抗菌剂的防污网材料、低表面能防污涂料、硅酸盐防污涂料.各种试验网衣于2002年4月开始进行浅海挂网试验,按编号顺序,将各组实验网片吊挂在实验海区生产网箱之间,吊挂深度为2～3 m,各实验网片之间保持1.5 m左右的间距,地点在浙江省佛渡的网箱养殖生产水域.通过每月吊挂一块新空白网片的方法来调查不同季节附着生物的种类和附着情况;每月1次定期对实验网片进行附着情况检查、拍照及称重,并进行试验海区理化因子的测定.结果证明几种防污材料,均具有一定的海洋防污能力.其中涂有硅酸盐防污涂料的网衣材料,其防污效果最佳.还根据试验结果讨论了这3种防污技术的机理、功效及影响因素.     

网箱网衣防污涂料的对比试验研究

通过定量测试、活生物养殖实验和海上挂样观察方法，对新研制的两种涂料与国内已应用的两种涂料、1种美国Flexgard水性涂料进行了涂料附着率、急性毒性和海上挂样网片防污效果对比试验。结果表明，新研制的两种涂料的使用量与美国Flexgard涂料水平相当；除新研制的1种涂料外，其余4种涂料均具有一定的急性毒性，尤以国内已应用的两种涂料毒性最大。防污效果，以新研制的N—15涂料和美国Flexgard涂料为好，挂样近7个月，生物附着仅为1～3级。在高温期间，未经防污处理的网片在1个月内生物附着增重率达到115．4％～157．7％。     

大型抗风浪网箱网衣防污涂料选优试验报告

2004年3月～2005年2月,在福建省围头海域对进口的13种配方和国产的14种配方的防污涂料开展防污效果选优试验.结果表明,进口的防污涂料中,以日本油脂公司提供、编号为X2、X3和x4的涂料,防污效果最好,缦海时间六个月时,其污损生物的面积覆盖率均≤3%;国产的防污涂料中,以厦门某研究所提供、编号为X11、X20和X27的效果最好,浸海时间六个月时,其污损生物的面积覆盖率均≤25%,且其价格远低于进口涂料,可作为春季、夏季和秋季进行网片防污处理的推荐涂料,供生产者选择.     

海水网箱网衣防污技术的研究进展

海水网箱养殖中,网衣污损附着物会影响网箱设施安全及其养殖鱼类的健康生长,因此,网衣防污是网箱养殖业备受关注的问题。本文在简述海水网箱网衣分类与特点的基础上,重点介绍了人工清除法、防污涂料法、机械清除法、金属合金网衣防污法、箱体转动防污法、生物防污法、网衣本征防污法等网衣防污技术最新研究进展;结合本课题组在网衣防污方面的研究成果,分析上述防污技术的特点,为网衣防污技术的深入研究以及水产养殖业的绿色发展提供参考。我国海水网箱养殖业大有可为,但网衣防污工作仍任重道远。     

XLP涂料对合浦珠母贝成活率、生长及附着生物量的影响

研究了XLP防污涂料对合浦珠母贝Pinctada fucata成活率、生长及附着生物量的影响。经XLP防污涂料处理后的贝，其附着生物量明显低于对照组；经防污涂料处理后的养殖网笼具，其附着生物量也明显低于对照组；贝和养殖网笼具同时用XLP防污涂料处理时，防生物附着的效果最好。经XLP防污涂料处理后，处理前期（30～60d）合浦珠母贝养殖成活率与对照组的成活率接近，或者略低于对照组；养殖120d后试验组成活率则高于对照组。使用XLP防污涂料处理后养殖120d，合浦珠母贝的个体大小及体重高于对照组。试验结果表明，使用XLP防污涂料能有效防御污损生物附着，有利于合浦珠母贝的养殖。     

毛蚶人工育苗最佳附着基的选择

为了找出毛蚶育苗当中最佳附着基,本文对几种附着基进行了对比试验,试验采用四种对比,即油泥、网衣、网片、直接附着在池壁上。结果发现,毛蚶人工育苗最佳附着基为潮间带表层油泥。稚贝生长快,成活率高,苗整齐,壳不挂脏。经过26d培育,成活率及生长速度分别为:油泥68%,平均壳长1.3 mm;网衣54%,平均壳长1.1mm;网片47%,平均壳长1.1mm;直接附着在池壁42%,平均壳长0.9mm。     

采用聚乙烯风衣作为扇贝育苗附着基的试验

本文报告了采用聚乙烯网衣作为虾夷扇贝，海湾扇贝稚贝附着基的附着效果，对变态幼虫至稚贝斯的生长和成活稚贝及附着期中间育成率等进行了对比试验，结果表明，采用网衣队基变态幼虫附着速度比棕帘慢，变态幼虫至稚贝的附着率及其日生长平均值分别为：采用网衣附着基，虾夷扇贝稚贝附着率为５１．９％，平均日生长为１８．２８μｍ，棕帘为５４％，１９．０μｍ，而海湾扇贝网衣为４９．９８％，２１．４μｍ，棕帘为５９％，２１．     

无公害海洋防污技术的研究进展

海洋中有2000多种污损生物,多数生活在海岸和海湾等近海海域。污损生物的幼虫和孢子能够漂浮游动,发展到一定阶段后就附着定居下来,污损海上设施,例如船体、浮标、桥墩、码头、网箱及网具等。海洋防污技术是用于防止海洋生物对海上设施的附着污损,起步于舰船防污涂料的研究,并以毒料释放型防污为主要技术途径,通过涂料中可释放的铜、锡、汞、铅等防污剂,在材料周围形成对海洋植物孢子     

采用聚乙烯网衣作为扇贝育苗附着基的试验

本文报告了采用聚乙烯网衣作为虾夷扇贝、海湾扇贝稚贝附着基的附着效果。对变态幼虫至稚贝期的生长和成活稚贝及附着期中间育成率等进行了对比试验。结果表明，采用网衣附着基变态幼虫附着速度比棕帘慢，变态幼虫至稚贝的附着率及其日生长平均值分别为：采用网衣附着基，虾夷扇贝稚贝附着率为５１．９％，平均日生长为１８．２８μｍ，棕帘为５４％，１９．０μｍ。而海湾扇贝网衣为４９．９８％，２１．４μｍ，棕帘为５９％，２１．０μｍ。稚贝中间育成率及单位水体出苗量分别为：虾夷扇贝网衣为２０．８％、６９．１７万枚／ｍ３，棕帘为１６．４３％、５８．５７万枚／ｍ３，海湾扇贝网衣为１８．９９％、８８．３万枚／ｍ３，棕帘为１８．３４％、６０．０万枚／ｍ３。     

美国大豆工业海洋网箱水产养殖技术近海海水鱼类养殖网箱工程技术手册（九）

（上接2010年第4期） 3．网衣的更换和清理 为了排除被有机体附着引起的生物污损造成的网片堵塞，在整个生产季节从一开始到生产周期的结束，都需要对网片进行定期的更换和清理。海洋网箱水产养殖技术网箱网衣的更换要借助于长袋网来完成，先从海洋网箱水产养殖技术网箱将鱼类用长袋网转运至临近的鱼类存放网箱。     

Tensile properties for netting materials used in aquaculture net cages

In order to perform a strength analysis of a net cage, it is crucial to know the tensile stiffness properties of the netting material. A new method for testing was established in order to determine the tensile properties of knotless netting materials. We applied it to a variety of netting materials and developed stress–strain relations. The stiffness was expressed as a constant value for relatively small strains, while for large strains the stress–strain relation was defined by a third degree polynomial. The average value of the constant stiffness for the tested wet netting materials was 81 N mm⁻² with a standard deviation of 9 N mm⁻² for strains less than 10%. For netting materials treated with anti-fouling paint, the average constant stiffness value was 131 N mm⁻² with a standard deviation of 13 N mm⁻² for strains less than 30%. The results are valid for uniaxial static loading of netting.     

Biofouling of salmon cage netting and the efficacy of a typical copper-based antifoulant

With the relatively recent advent of intensive aquaculture practices, there is a need for data on the contemporary biofouling and antifoulants associated with it. Therefore, experiments were conducted to yield data on the biological communities that develop on contemporary fish cage netting, both antifouled and untreated. The efficacy of a typical copper-based antifouling treatment was assessed through netting immersion trials performed at a salmon farm site in Clift Sound, Shetland. Over a 10-month period, regular samples were taken and data generated on the fouling biomass and species composition of the communities that developed. Furthermore, percentage net aperture occlusion values (PNO) were calculated with the aid of an image capture and analysis system, which is a methodology that shows excellent potential for use in future net fouling trials. Over the course of the trial, PNO values calculated from control netting rose quickly, but remained low for 150 days longer on treated nets; by day 210, PNO values were 98.72% and 3.06% for control and copper nets, respectively, immersed at 3 m. Following 10 months immersion, treated nets significantly reduced the biomass accumulation of biofouling compared to control nets (1.8 kg m^− 2 as opposed to 4.9 kg m^− 2). A total of 40 separate taxa were identified during the study, and species richness and composition data were significantly affected by the application of copper-based antifouling; for example, average species richness values were 16 and 9.75 for control and copper nets, respectively, immersed at 1 m. Of significance, the species Mytilus edulis and members of the Ascidiacea, including Ciona intestinalis and Ascidiella aspersa, were observed fouling the copper-treated netting.     

三苯基锡对褐菖鮋精巢发育的影响及其作用机制

三丁基锡(tributyltin,TBT)和三苯基锡(triphenyltin,TPT)广泛应用于海洋船只防污涂料。但相对于TBT,对TPT的毒性研究还很少。本实验以海洋经济鱼类褐菖鲉(Sebastiscus marmoratus)为对象,研究环境水平TPT对精巢发育的影响。研究发现,TPT降低精巢的精子数目和密度,增加精小叶间隙脂滴数量和精巢总脂质水平。另外,TPT降低精巢睾酮酯化水平,增加游离睾酮水平,降低游离17β-雌二醇水平。TPT对精巢发育的抑制可能与精小叶间隙脂质水平的增加及精巢17β-雌二醇水平的降低有关。实验结果为全面了解TPT产生鱼类生殖毒性效应、途径和机制提供了新的重要资料。环境水平的TPT能够抑制精巢的发育,而且毒性要高于TBT。这些结果为海洋环境政策的制定和评估有机锡污染对海洋鱼类资源的影响提供了重要的依据。     

Tensile properties for netting materials used in aquaculture net cages

In order to perform a strength analysis of a net cage, it is crucial to know the tensile stiffness properties of the netting material. A new method for testing was established in order to determine the tensile properties of knotless netting materials. We applied it to a variety of netting materials and developed stress–strain relations. The stiffness was expressed as a constant value for relatively small strains, while for large strains the stress–strain relation was defined by a third degree polynomial. The average value of the constant stiffness for the tested wet netting materials was 81 N mm⁻² with a standard deviation of 9 N mm⁻² for strains less than 10%. For netting materials treated with anti-fouling paint, the average constant stiffness value was 131 N mm⁻² with a standard deviation of 13 N mm⁻² for strains less than 30%. The results are valid for uniaxial static loading of netting.     

Resistance of aquaculture net cage materials to biting by Atlantic Cod (Gadus morhua)

Cod bite on aquaculture net cages has resulted in damages like frayed netting and holes, which in part can explain why cultured cod have escaped more frequently than salmon over the last years. We describe damages found on various netting materials subjected to cod bite through field experiments at commercial cod farms. Further, a method to test local cod bite resistance of traditional netting structures is suggested and initial results from a test jig prototype are given. Results from field experiments indicated that cod may have been attracted by types of netting that made it possible to draw filaments out of the twine, while stiff, coated netting structures and thick filaments showed no sign of bite damage during the test period. We concluded that netting materials for cod aquaculture must be resistant to cod bite or be repellent or uninteresting for cod. Based on the present findings, the better choice among the traditional netting materials seemed to be hard-laid netting materials, preferably with a primer that glues the filaments together.     

高分子编结网片水动力特性水槽试验研究

高分子渔用材料在设施养殖和海洋渔业中的应用越来越广泛,对其水动力特性进行研究十分必要。试验采用不同网目系数和网线粗度的高分子编结试验网片进行水槽试验,倾角从0°变化到90°,设置水流速度从0.3 m/s开始,以0.1 m/s为梯度,逐渐增大至1.3 m/s。为减小尾流和湍流对试验结果的影响,使用流线型框架固定装配。经试验得到以下结果:(1)在网片与水流垂直时,阻力系数有随网目系数增大而增大的趋势,而在网片与水流平行时,阻力系数随网目系数增大而减小。(2)阻力系数有随雷诺数增大而逐渐减少的趋势,网片平面与流体运动方向速度垂直时,阻力系数在13001500后阻力系数变化不大。(3)阻力系数随着冲角的增大而增大并最终趋于稳定值。(4)升阻力系数比(K)在总体上有随倾角变大而先变大再变小的趋势,K的极值均出现在20°到30°内,最大K值约为0.41。(5)网片与水流垂直时,在1000相似文献   

乙纶单丝捻线延伸性的研究

本项试验是研究乙纶(PE之一种)单丝捻制成的网线在外力小于断裂强力作用下所产生的变形特性(即延伸性)。网线的延伸性包括伸长、韧性和弹性三方面。本文的主要内容有：1．通过对乙纶网线结节(单死结)和无结拉伸断裂测试，得到了乙纶网线在1／2结节断裂强力作用下的伸长值；2．通过乙纶网线拉伸断裂试验时的拉伸曲线用三次样条函数(自然样条函数)插值法计算了网线的韧度和系数Q值，并编制了计算机程序；3．通过对乙纶网线定伸长弹性试验，计算在不同恢复时间下的弹性恢复率，从而得到定伸长弹性恢复率与网线直径和恢复时间的关系．     

Experimental study of the drag on fine-mesh netting

The hydrodynamic forces on netting have been investigated by many researchers. They proposed equations to estimate the drag and lift coefficients of the netting, taking the effects of the Reynolds number and solidity ratio into account. However, there are few studies on the hydrodynamic forces on netting with a fine mesh, which is sometimes used in Japan for farming small fish, such as young sardines. The size of the fine mesh is a few millimeters, whereas the solidity ratio of the netting is similar to that of standard netting. The drag on fine-mesh netting may increase because of the effects of blocking. In the present study, the drag on fine-mesh netting was examined by means of a towing experiment in a water tank. The experiment included an investigation of the drag on a planar net, a half-circular net, a circular net, and a circular net with a bottom, to understand the effect of the attack angle of the water current and wake. As a result, the drag coefficient of the plane net was in the range of those proposed in the previous studies. The effect of the attack angle of the water current was approximately reproduced by the cosine function. The reduction factors for the water current velocity through the circular net also agreed with those proposed in the previous studies, whereas it was approximately at the maximum among the previous estimations. Consequently, the drag on fine-mesh netting could be well explained by the estimates from the previous studies. However, the drag at the bottom of the net, parallel to the water current, was overestimated if hydrodynamic forces act on each transverse twine normal to the flow direction. The effects of the interactions among the twines, which are aligned parallel to the flow direction, should be specifically examined as a future study.     

四片式高口双拖网

本文反映黄海区群众渔业双拖网改进研究取得的一项新成果,报导了设计的依据、改进的特点、网模水池试验及海上实测的验证数据。经三年捕捞试验,取得了比原型网增产40％以上的显著效果。