Harmful algal blooms (HABs) have affected salmon farms in Chile since the early 1970′s, causing massive losses in fish. Two large HABs occurred in 2002 and 2009, during which Alexandrium catenella blooms killed tons of salmon over an extended geographic area in southern Chile. At the beginning of 2016, high and persistent densities of Pseudochattonella cf. verruculosa and A. catenella were detected in the estuarine and marine ecosystems of southern Chile. Mortality for this latter event reached 27 million salmon and trout (i.e. 39,000 tons). Unfortunately, the threshold concentrations of algae that could be harmful to the health of farmed salmon in southern Chile have not yet been quantified. Here, to protect fish farms from HABs, critical concentration levels, i.e. thresholds at which the behavior of farmed Salmo salar is affected by harmful algae were quantified using generalized linear mixed models (GLMM). An extensive database from southern Chile covering the period from 1989 to 2016 was analyzed. The database included salmon behavior, cell abundance of microalgae and oceanographic factors. For both species analyzed, the higher the cell abundance, the greater the probability of detecting anomalous behavior. A threshold of 397 cells/mL was estimated for A. catenella, although it can increase up to ca. >975 cells/mL at a Secchi depth >6 m and up to 874 cells/mL during flood tide. A threshold value <1 cell/mL for Pseudochattonella cf. verruculosa was found to be associated with anomalous salmon behavior, which significantly increased at a water temperature of 11 °C. Evidence for a relationship between fish behavior and mortality is provided.

自1970年代初以来，有害的藻华（HABs）就已经影响了智利的鲑鱼养殖场，造成了鱼类的大量损失。在2002年和2009年发生了两次大型HAB，在此期间，智利南部广泛的地理区域，亚历山大藻（Alexandre catenella）盛开导致大量鲑鱼死亡。2016年初，高密度和持久性假单胞菌比照。verruculosa和一个。连体毛虫在智利南部的河口和海洋生态系统中被发现。后一事件的死亡率达到2700万鲑鱼和鳟鱼（即39000吨）。不幸的是，尚未确定可能对智利南部养殖鲑鱼健康有害的藻类阈值浓度。在这里，以防止赤潮养殖场，临界浓度水平，即阈值，在其行为养殖大西洋鲑使用广义线性混合模型（GLMM）对受有害藻类影响的细菌进行了定量。分析了智利南部从1989年至2016年的大量数据库。该数据库包括鲑鱼的行为，微藻的细胞丰度和海洋学因素。对于两种分析的物种，细胞丰度越高，检测到异常行为的可能性就越大。估计A. catenella的阈值为397细胞/ mL ，尽管它可以升高到约200毫升。在大于6 m的Secchi深度时> 975细胞/ mL，在洪潮期间可达874细胞/ mL。假单胞菌的阈值<1细胞/ mL。绿藻被发现与鲑鱼异常行为有关，在水温为11°C时，鲑鱼行为明显增加。提供了鱼类行为与死亡率之间关系的证据。