Thanks — Sports fishing

This concerns the use of surface water for sport fishing purposes. Sports fishing is an important form of outdoor recreation and nature experience. An estimated 1.27 million Dutch fish on average more than 7 times a year (Hammen & De Graaf, 2013) in inland waterways. Nationally, there are 506,000 fishing fishermen affiliated with an angling association and an additional 81,000 sports fishermen are not affiliated but do own a Small VISpas. It is a growing form of recreation, since 2006 the number of affiliated sports fishermen has increased by 44 % (Sport Fishing Netherlands, 2014). Sport fishing generates an economic turnover of more than 700 million euros on an annual basis and high levels of employment (www.sportvisserijnederland.nl). The angling associations work together nationwide under the umbrella of Sportfishing Netherlands. For fishing, sports fishermen depend on good fish levels, access to the water and legal permission to fish the water. There is therefore a great deal of regional cooperation with water managers and local authorities who often bear the responsibility for these three factors. This cooperation often takes place within fish stocks management committees (www.visstandbeheercommissie.nl). Since the introduction of the Water Framework Directive (WFD), the water quality of surface water and the parameter fish in particular has become increasingly important. Since the water manager is responsible for improving water quality by the WFD, a lot of investments are made by Water Boards in achieving the ecological goals. Since 2011, the Netherlands has been conducting research into the use of the larger waters in the Netherlands by sport fishing. For most of these waters, the use of sport fishing has been identified (Sport Fishing Netherlands, 2014). In sports fishing, there is also a lot of research into fish stocks. Furthermore, sports fishermen themselves can register their catches via http://www.mijnvismaat.nl. This website uses 90,000 sports fishermen to keep track of their catches, more than 800,000 catches are recorded (www.mijnvismaat.nl). The sport fishing for pike takes place all over the Netherlands but the number of reported catches is higher in the WFD water bodies in the least populated part. In the map, pike catches are linked to the WFD water quality test of linear, flowing and still sweet waters (types R5, R6, R7, R8, R9, R10, R11, R12, R13, R14, R15, R16, R17 and R18 and M1 to M10). When testing the R and M water types according to the water quality, the better the water quality (good and moderate), the higher the pike catch. Poor water quality (untourage and bad) generally results in a low pike catch. The exception is the Utrecht region (Woerden) where good pike catches are recorded in water of poor water quality.本数据集围绕休闲垂钓对地表水域的利用展开。 休闲垂钓是户外休闲与自然体验的重要形式。据估算，荷兰年均有127万民众前往内陆水域垂钓，年均垂钓次数超7次（Hammen & De Graaf, 2013）。全国范围内，共有50.6万名垂钓者隶属于垂钓协会，另有8.1万名非协会会员的休闲垂钓者持有小型VISpas（Small VISpas）。该休闲方式近年来呈增长态势，自2006年以来，协会注册休闲垂钓者人数增长了44%（荷兰休闲垂钓协会, 2014）。 休闲垂钓每年创造超7亿欧元的经济营收与大量就业岗位（www.sportvisserijnederland.nl）。全国性的垂钓行业组织均在荷兰休闲垂钓协会（Sportfishing Netherlands）的统筹下开展合作。 休闲垂钓者的垂钓活动依赖优质的鱼类种群资源、水域可达性以及合法垂钓许可。因此，行业与水域管理者、地方政府开展了大量区域协作——后者通常承担上述三项条件的保障职责。此类协作多依托鱼类种群管理委员会（www.visstandbeheercommissie.nl）开展。自《水框架指令》（Water Framework Directive, WFD）实施以来，地表水域水质，尤其是鱼类相关参数的重要性日益凸显。根据该指令，水域管理者需负责改善水质，因此各水务董事会（Water Boards）为实现生态目标投入了大量资金。 自2011年起，荷兰针对本国大型水域的休闲垂钓利用情况展开研究。据2014年荷兰休闲垂钓协会的数据，多数大型水域的休闲垂钓利用情况已完成摸排。 休闲垂钓领域亦针对鱼类种群开展了大量研究。此外，垂钓者可通过http://www.mijnvismaat.nl平台登记垂钓渔获。该平台现有9万名注册垂钓者，累计记录超80万条渔获数据（www.mijnvismaat.nl）。 针对白斑狗鱼的休闲垂钓活动遍布荷兰全境，但在《水框架指令》覆盖的人口稀少区域的水体中，上报的渔获量更高。本数据集的地图将狗鱼渔获量与《水框架指令》覆盖的线性流动淡水、静水水体（类型涵盖R5、R6、R7、R8、R9、R10、R11、R12、R13、R14、R15、R16、R17、R18及M1至M10）的水质检测结果相关联。水质检测结果显示，水体水质越好（优良与中等），狗鱼的渔获量越高；水质较差（不合格与恶劣）时，狗鱼渔获量普遍偏低。乌得勒支省沃德伦地区为特例，该区域在水质较差的水体中仍有可观的狗鱼渔获记录。