Presence of Anisakis simplex (Rudolphi, 1809 det. Krabbe, 1878) and Hysterothylacium aduncum (Rudolphi, 1802) (Nematoda; Anisakidae) in runts of farmed Atlantic salmon, Salmo salar L.

One hundred farmed Atlantic salmon, Salmo salar L., were examined for the presence of nematodes by digestion of tissue in HCl-pepsin solution. All fish were sampled from one cage in a fish farm on the Norwegian south-west coast. Fifty harvest quality salmon, that is, salmon for human consumption (mean 5.4 kg, variation 3.0-7.6 kg), were sampled at the processing line while 50 salmon runts (mean 1.1 kg, variation 0.4-1.8 kg), discarded due to poor performance, were sampled from the discard bin after the grading station. Runts are individual fish with clear signs of poor performance over time and abnormal appearance and are thus not processed for human consumption. No nematodes were found in the musculature or viscera of the 50 harvest quality salmon. In total, 75 nematodes were found in 10 (20%) of the runts; 53 nematodes in the viscera and 22 in the musculature. Nematodes in the musculature were identified as Anisakis simplex (Rudolphi, 1809 det. Krabbe, 1878), while nematodes in the viscera were identified as A. simplex and Hysterothylacium aduncum (Rudolphi, 1802).