Red sea bream iridoviral disease

Red sea bream iridovirus

This fish disease can devastate an entire population of farmed fish. If it got to New Zealand, it could affect future aquaculture industries in warmer waters.

About red sea bream iridoviral disease (RSIVD)

RSIVD is a major cause of death of farmed red sea bream and more than 30 other farmed marine fish species. The disease was first recorded in Japan. It can also be found in many East and South-East Asian countries. Outbreaks are mostly seen in the summer season at water temperatures of 25°C and above.

Freezing an infected fish does not stop the virus. It can remain viable at temperatures down to minus 80°C.

Why this is a problem for New Zealand

Some of the species affected are closely related to fish we farm here (they are the same genus). The disease can kill up to 100% of a farmed fish population, depending on variables such as:

  • fish species
  • fish size
  • fish age
  • water temperature.

Other iridoviruses can cause similar diseases in ornamental freshwater fish.

How it could get here

The virus could come to New Zealand through:

  • infected live or dead finfish
  • contaminated equipment (such as nets and containers)
  • contaminated water.

Biosecurity New Zealand has strict measures in place to limit the chances of RSIVD making it through the border.

How to identify the disease

Diagnosing fish diseases requires laboratory testing. Signs of fish diseases are difficult to tell apart. You should report unusual numbers of fish deaths.

Report suspected cases

If your fish farm has an unusual number of fish deaths:

  • photograph the fish
  • put some of the dead fish in a plastic bag and refrigerate
  • call 0800 80 99 66

Note: This information is a summary of this disease's global distribution and potential impacts on New Zealand.

Last reviewed: