ABSTRACT

Growing demand for water requires resource managers to be innovative to minimise impacts on aquatic ecosystems. There are increasing concerns about fish damage and losses at water intakes, but few studies have examined the effectiveness of different screening material for excluding New Zealand fishes. We experimentally tested six screens (50–100 and 100–200 mm rock bunds, 3 mm woven mesh, 1.5, 2 and 3 mm wedge-wire), on two introduced and five native fish species. Bluegill bully (> 32 mm), common bully (> 30 mm), Canterbury galaxias (> 47 mm) and rainbow trout (> 40 mm) were screened effectively by 3 mm woven mesh and wedge-wire. Chinook salmon (> 43 mm) and īnanga whitebait (> 46 mm) were excluded by 2 mm wedge-wire, but shortfin elvers (< 80 mm) penetrated 3 and 2 mm wedge-wire, and glass eels (< 63 mm) penetrated 1.5 mm wedge-wire. Rock bunds were effective barriers for rainbow trout but were ineffective, and acted as habitat, for bluegill bully, Canterbury galaxias and shortfin eels. We recommend that 1.5 mm wedge-wire screens are used in the tidal zone of New Zealand rivers, 2 mm screens are used beyond this zone with an upstream transition to 3 mm screens dependent on catchment-specific fisheries values.

摘要

不断增长的水需求要求资源管理者进行创新，以尽量减少对水生生态系统的影响。人们越来越担心鱼类在进水口的损害和损失，但很少有研究检查不同筛选材料对排除新西兰鱼类的有效性。我们在两种引进鱼类和五种本地鱼类上通过实验测试了六个筛网（50-100 和 100-200 毫米岩石堤坝、3 毫米编织网、1.5、2 和 3 毫米楔形线）。蓝鳃鱼（> 32 毫米）、普通鱼（> 30 毫米）、坎特伯雷银鱼（> 47 毫米）和虹鳟鱼（> 40 毫米）通过 3 毫米编织网和楔形金属丝进行有效筛选。奇努克鲑鱼 (> 43 毫米) 和 īnanga 银鱼 (> 46 毫米) 被 2 毫米楔形金属丝排除，但短鳍幼鱼 (< 80 毫米) 穿透了 3 和 2 毫米楔形金属丝，玻璃鳗 (< 63 毫米) 穿透1. 5 毫米楔形线。岩石堤坝是虹鳟鱼的有效屏障，但效果不佳，并且充当了蓝鳃鲇、坎特伯雷星河鱼和短鳍鳗鱼的栖息地。我们建议在新西兰河流的潮汐区使用 1.5 毫米楔形丝网，在该区域以外使用 2 毫米网，上游过渡到 3 毫米网，具体取决于特定流域的渔业价值。