Spinal deformities in farmed Atlantic salmon

• Main Authors: Andrew M. Silverstone, Larry Hammell
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Canada; Atlantic salmon; Salmo salar
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.687.8475; http://tnfish.org/FrequentlyAskedQuestionsFAQ_TWRA/files/SpinalDeformitiesAtlanticSalmon.pdf

This article has been cited by other articles in PMC. Spinal deformities in farmed Atlantic salmon (Salmo salar) are often observed in intensive farming systems and result in production losses. Many putative factors have been implicated with the formation of spinal deformities in larger salmon. This condition has been described as broken back syndrome, curvy back disease, and short tails. Fish were obtained from an Atlantic salmon (Salmo salar) hatchery in eastern Canada. There had been no outbreaks of infectious disease in the previous 6 mo and no unexplained mortalities. Salmon smolts (approximately 30–100 g) were being transferred from the freshwater hatchery to marine net pens. During this process, the hatchery staff observed a higher than usual proportion of smolts with spinal deformities (Figure 1). No abnormal findings, other than spinal curvature, were detected on necropsy of 5 moribund Atlantic salmon smolts. Figure 1. Photograph of an Atlantic salmon smolt. Spinal lordosis and kyphosis are grossly apparent. The radiographic findings were spinal kyphosis and lordosis, shortened vertebral bodies, and pathological fractures of the vertebrae. The kyphosis involved the mid-spine, beginning at the 25th vertebral body; decreased rib spacing and collapsed and narrowed intervertebral spaces at vertebrae 18–36, which resulted in the associated intercostal spaces being asymmetric, were observed. The intervertebral space at th transition from kyphosis to lordosis was normal. There was no evidence of bridging callus or periosteal reaction (Figure 2). Figure 2. Radiograph of an Atlantic salmon smolt with spinal kyphosis and lordosis.