[Rob Wager is Bush Heritage's Freshwater Ecologist, responsible for ensuring the survival of the Red-fin Blue-eye, an endangered fish species found only in the artesian springs of Edgbaston Reserve.]
The springs at Edgbaston Reserve are so shallow that I didn’t think there was much chance of successfully filming the endangered Red-finned Blue-eye and Edgbaston Goby. Most underwater cameras are just too large for the shallow water in which Red-finned Blue-eyes live. But with a new generation rugged sports camera buried into the mud and vegetation, and the lens just poking out of the substrate but only just submerged, I was able to capture life from a spring fish's point of view.
In order to protect the fish we think it's important to understand how they interact with each other and how they utilise the habitat they live in. You can learn much walking around the springs, towering over the fish in their shallow water habitat. We've learnt that adult Red-finned Blue-eyes like to live in the slightly deeper water around the area where water flows from below the ground; that area may be just five centimetres deep. During the extended breeding season (spring, summer and autumn) red-finned blue-eyes scatter a few eggs over the algae substrate. The eggs are quite large for the size of the fish and they take about ten days to hatch. After the babies hatch we observe that they move into the very shallow parts of the spring where the water depth can be less than one centimetre. They like to live amongst the sedges and other plants growing in these areas. An interesting observation is that baby Red-finned Blue-eyes don’t have any red colouration. When you walk around the shallow areas you can see that they have a hint of blue and yellow.
But from an underwater perspective you can observe so much more. The baby Red-finned Blue-eyes appear quite spectacular, with vibrant blues and bright yellows. Why do they live in such shallow parts of the spring? What do they do there? What do they eat? Does anything eat them? Hopefully by using underwater cameras and getting a fishy perspective we can answer some of these questions.
The five photos attached to this blog post show a spring where red-finned blue-eyes live. As you can see the springs are not very large, often less than a city house block in area. The photo sequence takes you closer into the part of the spring with deeper pools, and then we look from above into a pool where the adults live. Look carefully and you can see the red fins of the mature males.
In the video link you can see some of the other creatures that share the habitat at Edgbaston Springs. Look carefully and you can see gastropod snails and tiny shrimps that are also unique to these springs. And then as the camera angle rises you can see red-finned blue-eyes. One of the surprises for me, and something I didn’t perceive from above, was that even in this shallow water (about 2 and a half centimetres deep) the blue eyes live mostly at the surface. There is still a lot to discover about these complex and diverse ecosystems.
Our work to protect the Red-fin Blue-eye is supported by the Queensland Government’s Everyone’s Environment grants program.