The Department of Forestry, Fisheries and the Environment (DFFE) says it continues to investigate the recent sardine mortality event on the West Coast, with pilchard herpesvirus (PHV) posited as the most likely explanation. The DFFE notes that when all the evidence outlined below is taken into account, it increasingly points to PHV as the leading explanation; however, its causal role will only be confirmed once the pathological and wider surveillance results are available.