ABSTRACT: Fish farm waste dispersal models are widely used but have only been directly validated to a limited extent. Two shallow (<20 m) Atlantic salmon farms (Bay of Meil and Quanterness) in Orkney, Scotland were studied. Bay of Meil has peak near-bed currents of 9.7 cm s^-1 whereas Quanterness has flows up to 31.6 cm s^-1. Sediment tray traps which allow resuspension to occur were deployed at each site. The patterns of particulate organic carbon (POC) deposition into the traps were in broad agreement with the observed water current directions and results from infaunal benthic monitoring. Despite the markedly different flow regimes at the 2 sites, most of the deposition occurred within 210 m of the cage perimeters. POC footprints were then modelled using the particle tracking model NewDEPOMOD. For Bay of Meil, a footprint was obtained using the recommended parameter defaults, but the spatial extent was too constrained compared to the sediment tray results. For Quanterness, all simulated particles were lost from the model domain and the critical erosion shear stress had to be increased to unrealistic levels to obtain a footprint. The failure to find a common set of parameter values applicable to both sites, despite their similar depths and sandy seabed, suggests that there remain unresolved issues, likely in how NewDEPOMOD handles waste resuspension. The sediment trays provided a direct method for quantifying the organic carbon deposition, facilitating direct validation of the dispersal model and demonstrating that further research is needed on fish farm waste dispersal at coarser sediment sites.

中文翻译：

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测量和模拟鲑鱼养殖场有机废物在沙质沉积物上的扩散

摘要：养鱼场废物消散模型被广泛使用，但仅在有限程度上得到直接验证。对苏格兰奥克尼群岛的两个浅海（<20 m）大西洋鲑鱼养殖场（梅尔湾和昆特内斯）进行了研究。梅尔湾的近床峰值水流为 9.7 cm s ^-1而 Quanterness 的水流高达 31.6 cm s ^-1。每个地点都部署了允许重新悬浮的沉积物托盘捕集器。颗粒有机碳（POC）沉积到捕集器中的模式与观察到的水流方向和底栖动物监测结果基本一致。尽管两个地点的流态明显不同，但大部分沉积发生在笼周界 210 m 范围内。然后使用粒子跟踪模型 NewDEPOMOD 对 POC 足迹进行建模。对于梅尔湾，使用推荐的默认参数获得了足迹，但与沉积物托盘结果相比，空间范围过于受限。对于 Quanterness，所有模拟颗粒都从模型域中丢失，并且必须将临界侵蚀剪切应力增加到不切实际的水平才能获得足迹。尽管两个地点的深度和沙质海底相似，但未能找到适用于这两个地点的通用参数值，这表明仍然存在未解决的问题，可能是 NewDEPOMOD 如何处理废物再悬浮的问题。沉积物托盘提供了一种量化有机碳沉积的直接方法，有助于直接验证扩散模型，并表明需要对较粗沉积物处的养鱼场废物扩散进行进一步研究。