When most people think of tropical aquatic animals, saltwater species such as whales, sharks and stingrays usually come to mind, rather than those that live in fresh water. That’s not surprising given that salt water covers more than 70 per cent of the earth’s surface, while fresh water covers a mere one per cent. However, of the 40 per cent of the known freshwater fish species, one group may seem a little out of place – the stingrays of the Amazon Basin.
The Vancouver Aquarium Marine Science Centre is home to more than 100 species of tropical freshwater fish, including three species of freshwater stingrays. These stingrays adapted to freshwater when the Amazon Basin turned from a salty inland sea into a freshwater environment millions of years ago.
Of the three species at the Aquarium, the tiger stingrays have provided the most excitement recently, with the female giving birth to three pups. Currently residing behind the scenes, their progress is being monitored by our biologists.
Athena, the biologist responsible for the Aquarium’s freshwater fishes, says, “It’s really enjoyable to be able to work with this species of freshwater ray, noting the changes in colour pattern, and monitoring food preferences as they grow. We’ve been able to share our success by exchanging information with other accredited zoos and aquariums.”
The tiger stingray, Potamotrygon tigrina, only formally described by science (given a name) in 2011, is now part of a population and breeding conservation plan; the Vancouver Aquarium was one of the first accredited zoos and aquariums in North America to rear this species.
Females are able to reproduce at approximately five years of age and the gestation period is about five months long, depending on water temperature. While our female recently gave birth to three, one or two pups is more common.
Tiger stingrays, like most species of stingrays, have venomous barbs in their tails that are primarily used in defense. Stingrays generally do not attack aggressively or even actively defend themselves – most often when threatened, their primary reaction is to swim away. At the Aquarium, careful handling and the proper protective equipment are required for the care of these animals.
For now, visitors to the Vancouver Aquarium can view the female tiger stingray in the Amazon Flooded Forest exhibit and the two males, in the exhibit beside the piranhas – and those are another story!