Researchers in British Columbia have developed a new, faster way of testing salmon for diseases, revealing infection before the fish appears visibly sick.
Usually, scientists investigating a salmon's death would examine a tissue sample under a microscope or culture a viral sample over several days to isolate the cause of the disease.
The new test involves analyzing the activity of certain genes in living salmon, allowing for early detection of viral infections, and has already led to the discovery of eight new viruses in B.C.'s waters.
"It's pretty groundbreaking," said Kristi Miller, head of molecular genetics at the federally-run Pacific Biological Station in Nanaimo.
Wild salmon, farmed salmon
Miller studies juvenile salmon migrating in the ocean and wanted to develop a tool to detect earlier stages of diseases. If a salmon gets diseased in the wild, they are vulnerable to predators and death.
In the wild, about 90 per cent of salmon entering the ocean will die before they return to spawn.
Scientists don't often have the chance to observe mortality in oceans, but it's key to understanding the declining numbers of salmon, Miller told CBC host of The Early Edition Stephen Quinn.
"We don't really understand what the role of infectious disease processes are in those mortalities and, more importantly, in the salmon decline that are being experienced by multiple species over the last 20 years," she said.
Early detection of viruses is also important in farming, Miller said, because it means the spread of the disease could be controlled to reduce impact.
The way a virus acts in a sick salmon is not all that different from other species with diseases.
"It's very possible that this tool could be used for other wildlife species, in whales or bears or any kind of other reptile or mammal species," Miller said.
With files from The Early Edition.