The influence of the pycnocline and cage resistance on current flow, oxygen flux and swimming behaviour of Atlantic salmon (Salmo salar L.) in production cages
The influence of the pycnocline and cage resistance on current flow, oxygen flux and swimming behaviour of Atlantic salmon (Salmo salar L.) in production cages
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DOI：
10.1016/j.aquaculture.2006.12.047
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发表时间：
2007-05-01
期刊：
影响因子：
4.5
通讯作者：
Ruohonen, Kari
中科院分区：
文献类型：
--
作者：
Johansson, David;Juell, Jon-Erik;Ruohonen, Kari
选址是最佳养鱼条件的关键。为了能够估计场地的持水量，了解影响水质的物理、化学和生物过程是很重要的。在这项研究中，对挪威西海岸四个商业鲑鱼养殖场的氧气、温度、盐度和水流进行了详细的垂直测绘，时间为初秋两周，并与笼养鲑鱼的游泳深度和鱼群密度有关。在所有因素中都观察到了广泛的差异，无论是在站点内还是在站点之间。简而言之，影响农场水流的跃层强度和笼子阻力被发现是影响其他环境条件的主要因素。跃层的出现影响了氧气和水流的深度分布以及鱼类的行为。分层站点的平均氧气水平低于均匀站点的平均氧气水平。在4个位置中的3个位置发现流过笼子的电流显著减少，这导致笼子内的氧气水平低于笼子外的水平。调查结果强调了在制定适当的选址方案过程中了解网箱环境动态的重要性。此外，笼养管理应同时考虑到跃层的存在和笼养系统对氧气水平的影响，以确保可接受的动物福利标准和有效的生产。(C)2007爱思唯尔B.V保留所有权利。
Site selection is critical for optimal fish farming conditions. To be able to estimate the holding capacity of a site, it is important to understand the physical, chemical and biological processes that affect water quality. In this study detailed vertical mapping of oxygen, temperature, salinity and water currents was performed at four commercial salmon farms on the west coast of Norway for 2 weeks in early autumn and related to the swimming depth and schooling density of the caged salmon. Wide variations were observed in all factors, both within and between sites. Briefly, the strength of the pycnocline and the cage resistance, which affected the flow of water through the farm, were found to be the main factors influencing the other environmental conditions. The occurrence of a pycnocline influenced the depth profiles of oxygen and the current as well as fish behaviour. Lower mean oxygen levels were observed at stratified sites than at homogeneous sites. A major reduction in the current passing through the cages was found on three of 4 sites, which led to lower oxygen levels inside than outside the cages. The results of the survey underline the importance of understanding the dynamics of the cage environment in the process of developing appropriate site selection protocols. Furthermore, cage management should take both the existence of a pycnocline and the influence of the cage system on oxygen levels into consideration to ensure acceptable animal welfare standards and efficient production. (C) 2007 Elsevier B.V All rights reserved.