Scientists probe if herpes virus is killing sardines off South Africa

Scientists in South Africa are investigating why masses of sardines have washed up dead or dying along parts of the country’s west and south coast – and if a herpes virus detected in the fish is responsible.

The mass mortality of sardines this month has so far stumped the country’s Department of Forestry, Fisheries and the Environment, though scientists have come to at least one conclusion: it is the first time that the virus in question – pilchard herpesvirus, or PHV – has been identified in sardines off South Africa.

PHV, which was linked to two mass sardine mortality events in Australia in the 1990s, can cause inflammation and thickening of sardines’ gills, which interferes with their oxygen uptake, according to the South African environment department.

Sardines and pilchards are the same type of fish, with sardines being the younger, smaller ones.

PHV is a fish virus and poses no known risk to human health, the department said, and its detection does not mean that healthy sardines caught commercially or canned sardine products are unsafe to eat.

Dozens of sardines taken from affected areas, some dead and some alive, are being examined by scientists at the South African Institute for Aquatic Biodiversity and a local university.