The fish kills which occurred in Pago Pago Bay in April was probably caused by a virus.
This was the conclusion of laboratory analyses conducted by Dr. Thierry Wok and colleagues of the United States Geological Survey.
Director of Marine and Wildlife Resources – Dr Ruth Matagi-Tofiga, said in a press release announcing the test results that 7 out 10 fish examined had myelitis non-suppurative showing degrees of inflammation in the spinal cord, particularly near the fish tail.
The spinal cord is a bundle of tissues that are enclosed in the backbone of the fish that runs from the brain to the tail and where nerves to other parts of the body connect. Both the brain and the spinal cord are parts of the nervous system.
A virus is a small infectious agent that replicates itself by inserting itself inside the cells of other organisms.
It is not known at this point what type of virus caused the fish kills and how the virus was contracted.
The first fish kills were recorded April 5 -8, 2016 and mostly consisted of newly-arrived rabbit-fish.
Several thousands of dead rabbit-fish were recorded in Amouli and Laulii, with Alao reporting the same occurrence later.
The DMWR Director explains that many fish on the reef have babies that spend several days to weeks in the ocean after being spawned and arrive on the reef to spend the rest of their fish life.
On the later weeks, fish kills mostly consisted of the rabbit-fish.
DMWR staff said the dead fish were newly-arrived to the reef based on their size.
In addition, April is part of the spawning season of fish in American Samoa.
