Rare Sawfish release heralds research opportunities at Cairns Aquarium
On Tuesday 28th November, Cairns Aquarium will introduce the first of two, critically endangered, sawfish to the 300,000 litre River Monsters exhibit which is the largest freshwater aquarium exhibit in Australia.
A male and a female freshwater sawfish, Pristis pristis, arrived at Cairns Aquarium several weeks ago. The male, the larger of the two weighed in at 17.3kg and 1.71m in length and the female weighed 8.4kg and measured 1.36m when introduced to the quarantine tank. In quarantine they have been monitored and trained to target feed, to ensure that when released into the exhibit, these bottom feeding animals will not be outcompeted by fishes that feed higher in the water column.
Now the male is eating well and swimming comfortably it will be the first to be released into its new home and it is expected that the female will follow in a few days.
The freshwater sawfish, also known as the largetooth sawfish is one of the planet’s largest fish, growing to over 6.5m in length. While they swim much like sharks, they are actually a species of ray. The most distinctive feature of the sawfish is its long, flattened, tapered snout, called a rostrum, which may measure up to a fifth of the total length. Along the edge of this blade are a series of 16 to 20 evenly-spaced, long, thin teeth, creating the appearance of a ‘saw’. It is this saw that has contributed to the decline in numbers of these mazing animals as they are hunted for their unique and peculiar rostrum, fins and meat. Over-fishing and the degradation of important estuarine and freshwater habitats have also contributed to their critically endangered IUCN status.
Northern Australia represents one of the only remaining population strongholds for this sawfish and although it has also declined significantly here, it is holding on. “The likelihood of seeing these amazing animals in the wild is virtually non-existent, so having two of them on display will make for a real spectacle” General Manager Julie Cullen said. “They are very special creatures that move from salt to freshwater throughout their life cycle and we hope that people will become more aware of their conservations status as a result of seeing them, and hearing about them, at Cairns Aquarium” she said.
In October, the Cairns Aquarium commissioned a hand crafted 5.3m fibreglass replica sawfish which was installed on the wall opposite the Sawfish exhibit.
“We wanted to show visitors a life size model to demonstrate just how large and impressive these amazing fish can grow to. It’s been a really eye-catching exhibit and people are completely surprised that these river monsters exist in the fresh water tributaries flowing inland from the Gulf of Carpentaria and top end.” Cullen said.
Freshwater sawfish grow slowly, reaching maturity late at 10 years of age and producing few young. As a result, their population growth is extremely low. Although lifespan in the wild is unknown, research suggests this species lives roughly 30 years. “It is the research opportunities that these two animals provide that is of great interest to Cairns Aquarium” said Head Curator, Ramon Barbosa. “We are already engaging with facilities that have a vested interest in sawfish research and we also plan to undertake our own research programs in the future. We need to build our knowledge of this iconic species if we are to have a hope of preserving the northern Australian populations for the future” he explained.