The smoltification phase of Atlantic salmon aquaculture involves a critical physiological transition with significant welfare implications if poorly managed.
Salmon transferred before completing smoltification cannot regulate salt and water balance in seawater, causing chronic osmotic stress, reduced appetite and increased susceptibility to disease. Artificial light manipulation to trigger smoltification can cause cataract development and other ocular problems. Crowding during grading and transfer operations causes acute stress. Best practice involves careful physiological assessment before transfer and minimising handling frequency during the vulnerable smoltification window.