The effects of harmful algae on bivalve physiology are complex and involve both physiological and behavioural responses. Studying those responses is essential to better describe and predict their impact on shellfish aquaculture and health risk for humans. In this study we recorded for two months the physiological response of the blue mussel Mytilus edulis from Eastern Canada to a one-week exposure to a paralytic shellfish poisoning producing dinoflagellate strain of Alexandrium catenella, isolated from the St Lawrence estuary, Canada. Mussels in a ‘control’ treatment were fed continuously with a non-toxic diet, while mussels in a ‘starvation’ treatment were fed the same non-toxic diet the first week and subsequently starved for seven weeks. Mussels in a ‘toxic’ treatment received A. catenella for one week before being starved until the end of the experiment. Over a two-month experiment we monitored shell and tissue growth, filtration capacity, respiration rate, byssal attachment strength, valve opening behaviour, and toxin content in tissues. Mussels fed normally on the toxic dinoflagellate and accumulated an average of 51.6 µg STXeq 100 g^–1 after one week of exposure. After seven weeks of depuration, about half of the specimen showed levels around 18 µg STXeq 100 g^–1. The condition index of exposed mussels (‘toxic’ treatment) decreased rapidly from the start as compared to mussels that received a one-week non-toxic diet (‘starvation’ treatment). Oxygen consumption rates increased in the ‘toxic’ treatment before leveling out with that of mussels from the ‘starvation’ treatment. Valve opening amplitude was lower in the ‘toxic’ treatment during and following the exposure. Average valve closure duration was higher right after the exposure, during the peak of mussel tissue intoxication. No significant change in byssal thread strength was observed through time in each treatment but less force was required to detach mussels from the ‘toxic’ and ‘starvation’ treatments. The number of byssus threads produced by mussels exposed to the toxic dinoflagellate was also lower than in the control group. These results represent advancements in our understanding of the impacts of harmful algae on bivalves and contribute to the development of mitigation measures necessary to both the safety of consumers and the sustainability of aquaculture operations.

有害藻类对双壳类动物生理的影响是复杂的，涉及生理和行为反应。研究这些反应对于更好地描述和预测它们对贝类水产养殖和人类健康风险的影响至关重要。在这项研究中，我们记录了来自加拿大东部的蓝贻贝Mytilus edulis 对从加拿大圣劳伦斯河口分离的产生链鞭毛藻的麻痹性贝类中毒一周的生理反应，记录了两个月的生理反应。“对照”处理中的贻贝连续饲喂无毒饮食，而“饥饿”处理中的贻贝在第一周饲喂相同的无毒饮食，随后饥饿七周。接受“有毒”处理的贻贝A. catenella饥饿前一周，直到实验结束。在为期两个月的实验中，我们监测了壳和组织的生长、过滤能力、呼吸速率、肺附着强度、瓣膜打开行为和组织中的毒素含量。贻贝通常以有毒的甲藻为食，暴露一周后平均积累了 51.6 µg STXeq 100 g ^–1。净化 7 周后，大约一半的样本显示出约 18 µg STXeq 100 g ^{–1 的水平}. 与接受为期一周的无毒饮食（“饥饿”治疗）的贻贝相比，暴露的贻贝（“有毒”治疗）的状况指数从一开始就迅速下降。在与来自“饥饿”处理的贻贝的耗氧率持平之前，“有毒”处理的耗氧率增加。在暴露期间和暴露之后，“有毒”处理的阀门打开幅度较低。在贻贝组织中毒的高峰期，暴露后的平均瓣膜关闭持续时间更长。随着时间的推移，在每次处理中都没有观察到底线强度的显着变化，但是将贻贝从“有毒”和“饥饿”处理中分离所需的力较小。暴露于有毒甲藻的贻贝产生的byssus线数量也低于对照组。