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首页> 外文期刊>Aquaculture Research >Empirical measurements of parameters critical to modelling benthic impactsof freshwater salmonid cage aquaculture
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Empirical measurements of parameters critical to modelling benthic impactsof freshwater salmonid cage aquaculture

机译：对淡水鲑鱼网箱养殖底栖影响建模至关重要的参数的经验测量

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Although the waste dispersion models used in salmonid marine cage aquaculture could potentially be applied in freshwater cage aquaculture, much of relevant data on the waste particle parameters are unavailable. The present study provides new data on the wet densities of diets, the fall velocities of diets, the fall velocities of faecal matter and waste particle size. A significant increase of densities caused by the immersion time in water was observed, The wet density obtained from 60-s immersion time was found to be the effective settling density of diets. Fall velocities of salmonid diets were non-Stokesian and ranged from 0.02 to 0.12 m s(-1). These fall velocities did not significantly vary with water temperature. Fractionation of collected solid wastes from experimental tanks revealed that almost 60% by mass was retained on 2000-, 1000- and 500-mu m meshes. The fall velocities of these fractions were found to vary between 0.015 and 0.030 m s(-1). The waste fraction that passed through a 500-mu m mesh had an estimated median diameter of 114.4 mu m. The observed fall velocities of both diets and solid wastes were lower than those commonly used in modelling waste dispersion in the marine environment. However, because of the relatively slow current velocities in most freshwater environments, it is expected that the wastes will lend to accumulate locally at cages.
机译：尽管用于鲑鱼网箱养殖的废物扩散模型有可能应用于淡水网箱养殖，但尚无许多有关废物颗粒参数的相关数据。本研究提供了日粮的湿密度，日粮的下降速度，粪便物的下降速度和废物粒径的新数据。观察到由在水中浸泡时间引起的密度显着增加。发现从60 s浸泡时间获得的湿密度是日粮的有效沉降密度。鲑鱼饮食的秋天速度是非斯托克斯式的，范围为0.02至0.12 m s（-1）。这些下降速度并未随水温显着变化。从实验罐中收集的固体废物经分级分离后发现，在2000、1000和500微米筛孔上保留了近60％的质量。发现这些馏分的下降速度在0.015和0.030 m s（-1）之间变化。穿过500微米筛孔的废物部分的估计中值直径为114.4微米。日粮和固体废物的观测速度均低于模拟海洋环境中废物扩散的常用速度。但是，由于大多数淡水环境中的流速相对较慢，因此预计废物将在网箱中局部堆积。

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