Survival of Atlantic Salmon (Salmo salar L.) and

• Main Authors: Episodic Acidification, Spring Flood, Ignacio Serrano, Supervisors Eva Brännäs, Hjalmar Laudon
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Atlantic salmon; Northern Sweden; Salmo salar
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.569.9973; http://ex-epsilon.slu.se:8080/archive/00000630/01/Survival_of_Atlantic_Salmon_and_Brown_trout_to_episodic_acidification.pdf

This study was designed to evaluate the survival of Atlantic salmon (Salmo salar) and brown trout (Salmo trutta) parr (1+) during the spring snow melt period in order to identify variables that best explain differences in fish survival among streams, and to define critical toxicity thresholds in organic rich waters. The experiments were carried out in 10 streams in northern Sweden. Different hydrological parameters were monitored continuously, and water samples for chemical analysis were collected throughout the experimental period. During the spring snow melt, DOC concentration increased strongly, causing a natural depletion of pH and an increase in total aluminium, which resulted in high fish mortality. Atlantic salmon was more sensitive than brown trout to acidic water in all streams during the experiments. Also, the mortality data confirmed that pH and ANC/H+ ratio constitute good predictors of Atlantic salmon and brown trout survival. The results also suggest that fish in DOC-rich streams can tolerate higher acidity and inorganic aluminium levels than fish in low DOC systems. Accordingly, a critical chemical threshold of pH (5.9 and 5.1) can be defined for Atlantic salmon and brown