In a sustainable production of animals, monitoring and minimizing mortality must be a top priority. Systematic measuring of mortality over time can be used to evaluate the impact of changes in management and production strategies in Norway. To aid understanding of the potential for reducing mortality, we have used data from 2014 to 2018 to investigate the spatio-temporal patterns of mortality, by descriptive analyses and statistical modelling of possible determinants of mortality. The results show large differences in mortality across different production zones and between years. The areas with the highest density of farmed salmon are also the ones with highest mortality. The total cumulated mortality of farmed salmon increased from 32.3 million in 2014 to 35.2 million in 2018, corresponding to 14.3% and 15.8% of the standing stock. An initial higher mortality was observed during the first 3 months after stocking (mean: 1.5% [0.9%-8.6%] mortality/month). This was followed by a period of stability and lower mortality (mean: 0.8% [0.9%-3.1%] mortality/month), until month 10, when mortality started to increase again. The month of first stocking, the year of slaughter, production zone and number of months at sea were all found to be statistically significant determinants for mortality, with p-values < 1e-15.

中文翻译：

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挪威大西洋鲑（Salmo salar）海水生产阶段死亡率的时空变化。

在可持续的动物生产中，监测和降低死亡率必须是重中之重。随时间推移死亡率的系统测量可用于评估挪威管理和生产策略变化的影响。为了帮助了解降低死亡率的潜力，我们使用了2014年至2018年的数据，通过对可能的死亡率决定因素的描述性分析和统计模型来研究死亡率的时空格局。结果表明，不同生产区域之间以及不同年份之间的死亡率差异很大。养殖鲑鱼密度最高的地区也是死亡率最高的地区。养殖鲑鱼的总累积死亡率从2014年的3,230万增至2018年的3,520万，分别占常备种群的14.3％和15.8％。放养后的头三个月观察到最初较高的死亡率（平均：每月死亡率为1.5％[0.9％-8.6％]）。接下来是一段稳定和较低的死亡率（平均：每月0.8％[0.9％-3.1％]死亡率），直到第10个月，死亡率又开始增加。发现首次放养的月份，屠宰的年份，生产区和海上月份的数目均是死亡率的统计学上显着的决定因素，p值<1e-15。