The Chinese sturgeon, like salmon, lives in both saltwater and freshwater. They lay their eggs high up in the river, where they live for about a year before swimming down to the sea.
They do not return to the river for another 12 to 18 years, when they lay eggs in their birthplace.
Female sturgeon can carry up to 1.3 million eggs in one pregnancy, but fewer than 1 per cent hatch successfully. The eggs are fertilised externally.
Unlike salmon, which die after spawning, sturgeon return to the ocean after laying their eggs. They go through this reproduction cycle three or four times in their lifetime.
Like those in the wild, the nine Chinese sturgeon that were given to Ocean Park were born in freshwater. The five that were sent to Hong Kong last month had lived in saltwater on the mainland before they were delivered.
The new batch will not go through adaptation to saltwater until they arrive. Not much research had been done on Chinese sturgeon in a saltwater environment, and this was the reason for creating one for those in Ocean Park, said Suzanne Gendron, its executive director of zoological operations and education.
