Don’t Try to Whisper to Your Salmon Fillet
Next time you are out to dinner and order that delicious Atlantic salmon, the chances are that it is a fillet of a farm-bred fish. Well! Don’t try to whisper to your dinner because there is about a 50 percent chance that the fish had a hearing loss. Scientists in Australia have discovered that approximately 50 percent of farm-bred salmon have a deformed otolith, the fish’s ear bone, which very likely gives them hearing loss. The deformity appears to occur early in life, and the hearing loss is speculated to get worse as the fish matures. The particular deformity seems to be ten times more likely in farm-raised salmon as compared to wild stocks. It seems clear that some specific aspect of the farming process is causing the deformity, but the exact cause is yet unknown.
On the face of it, salmon that does not hear as well could be dismissed as a problem not worth paying attention. After all the filet still tastes just as delicious. However, producing farmed animals with known deformities violates the ethical standards, and even legal criteria in some countries, related to animal farming. There may be another important connection to a mystery that makes hearing problems in farm raised salmon an important one to understand and solve. Every year, billions of farm-bred juvenile salmon are released into rivers as part of fish conservation programs. However, these salmon are 10 to 20 times less likely to survive as compared to wild salmon. Could the hearing loss in the farm-bred salmon prevent them from detecting predators and navigating efficiently to breeding grounds?
Hannink N. (2016) Farmed-Salmon Hard of Hearing. University of Melbourne.