Biosecurity for fishfarming cage systems due to the highly clogged screen aggravated by Limnoperna fortunei

ABSTRACT This research evaluated degree of clogging by Limnoperna fortunei in different materials for wire mesh fabrication, the dynamics of mollusk sealing and the cost-benefit ratio of these materials used in tank-nets. Samples of single-twist screens of 19 mm mesh were used, from five different types of coatings were placed in the Salto Caxias dam on the Iguaçu River in the Paraná state, between July 2012 and July 2014. Every six months, it was verified the weight gain of the screens due to clogging and counting of the number of mussels adhered. After the data collection was performed Kruskal-Wallis statistical test to evaluate the weight gain of the screens due to clogging. In addition, a survey was carried out with 21 companies to obtain the commercialized price of screens for the production of net tanks and to evaluate the expected durability of the materials. The different materials evaluated for the screens influenced the sealing and adhesion of the golden mussel. In addition, the most cost-per-year screen is that of plastic-coated galvanized wire and for low clogging it is the Bezinal wire.

摘要：本研究评估了不同金属丝网制备材料受沼蛤（Limnoperna fortunei）堵塞的程度、软体动物附着封堵的动态过程，以及此类材料应用于水产网箱时的成本效益比。本研究选取五种不同涂层材质的19毫米网孔单捻丝网样品，于2012年7月至2014年7月间放置于巴西巴拉那州伊瓜苏河的萨尔托卡克西亚斯坝水域中。每半年对丝网因堵塞产生的重量增量进行测定，并统计附着贻贝的数量。数据采集完成后，采用克鲁斯卡尔-沃利斯（Kruskal-Wallis）检验对丝网的堵塞重量增量开展统计分析。此外，本研究对21家相关企业开展调研，获取网箱生产用丝网的商品化售价，并评估各受试材料的预期使用寿命。研究结果表明，本研究所评估的不同丝网材料对沼蛤的附着与网孔封堵行为存在显著影响。其中，单位年度使用成本最低的丝网为涂塑镀锌钢丝网，而抗低堵塞性能最优的则为贝齐纳尔（Bezinal）钢丝网。