Temperature effects on VEN progression in Pacific herring

Viral erythrocytic necrosis (VEN) is a condition affecting red blood cells of marine and anadromous fish in the Atlantic and Pacific oceans. Epizootics periodically occur in wild populations of juvenile Pacific herring and have been associated with mass mortality in Alaskan herring populations in the 1980's. Several field studies have reported increased infection prevalence during the summer months when ocean temperatures are at their warmest. In this study age 1 Pacific herring were exposed to VEN at 3 temperatures (6.9, 9.0, 13.5 C) and monitored for 44 days. Infection prevalence, viral load and percent of fish positive increased with increasing temperatures. Liver samples for RNASeq were assessed from the 6.9 and 13.5 C treatments on days 10 and 34.