Identifying and managing non-infectious diseases in aquaculture is critical to sustaining productivity and improving efficiency. In coho salmon aquaculture, these conditions account for a high—and rising—proportion of total mortality. This study characterizes pathological conditions affecting coho salmon (Oncorhynchus kisutch) farmed in southern Chile, drawing on clinical cases collected between 2020 and 2025 from sites in the Los Lagos (X) and Aysén (XI) regions.
Major non-infectious conditions observed include spontaneous vertebral fractures, focal linear melanosis, gastric impaction, gastric dilation/bloat, lipid cysts, and skeletal deformities. Spontaneous vertebral fractures were mainly detected in the marine grow-out phase, often during the final third of the cycle, and were associated with acute mortality, spinal deviation, vertebral compression, and hemorrhages in adjacent musculature. Focal linear melanosis was frequently located in the ventral anterior fillet, linked to rib fractures and chronic inflammation. Gastric impaction and dilation were associated with environmental factors (low oxygen, high temperatures, harmful algal blooms), feeding practices, and possible osmoregulatory dysfunctions. Lipid cysts were more frequent in fish with high visceral fat content, rapid growth, and good nutritional status. Skeletal deformities, predominantly in the caudal peduncle, were related to incubation temperature and had significant impacts on processing quality and fish welfare.
The multifactorial etiology of these conditions highlights the need for multidisciplinary approaches, standardized diagnostic techniques, and proactive management strategies to reduce their incidence and impact. This study provides updated insights into the prevalence, pathological features, and risk factors of non-infectious diseases in coho salmon aquaculture in Chile, contributing to improved health management and production sustainability.