A theme park in Hong Kong is reported to be mystified after six of its 14 Hammerhead sharks died at its aquarium, all within a period of just seven hours.
Ocean Park said the remaining eight sharks in its care were also at risk and were being closely monitored.
The dead sharks — all females aged about five years — succumbed to a mystery disease one by one, after staff found them 'swimming abnormally' at the weekend.
Up until that time vets at the park said the sharks had showed no signs of being ill and there were no external injuries. The affected sharks were transferred to a back-of-house area for treatment and monitoring, but they died.
The sharks had been at the aquarium for three years, during which time they were reported to have grown well and doubled their weight.
Post-mortems are being carried out to try and determine the cause of the deaths.
Suzanne Gordon, executive director of the park's zoological operations and education, said: "We are completely committed to determining the cause of the situation, from reviewing water quality to a potential disease outbreak affecting hammerhead sharks.
"We are doing our best to ensure the health of the remaining sharks and other marine species."
All the other inhabitants of the Grand Aquarium, where the sharks that died were on display, are reported to be behaving normally.
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