Snorkelling boffins’ fishy find
SCIENTISTS snorkelling in creeks in the Daintree have recorded tiny fish capable of swimming as fast as Olympic gold medallist Ian Thorpe in his heyday.
Their efforts have proved a valuable scientific tool for research into goby fish.
TropWATER researcher James Donaldson did his honours study with the Australian National University supervised by Dr Chris Fulton and TropWATER and CSIRO post-doctoral fellow Dr Brendan Ebner and their research has been published in the journal Freshwater Biology.
Their focus was on the goby fish, found throughout Australia but predominantly in tropical regions around the Pacific, an interesting fish which have two fins on the underside of their body fused together forming a section cup to help them to cling to rocks in high flow.
The researchers snorkelled in Emmagen Creek and Oliver Creek in Cape Tribulation and recorded interesting observations about two species, the rabbit- headed goby ( Sicyopterus lagocephalus) and the orange- mouthed goby ( Schismatogobius).
‘‘We looked at six species that live together in a stream and compared them,’’ Mr Donaldson said.
‘‘What we found was driving the differential distribution niches in an ecosystem wasn’t to do with depth or composition of the bottom of the system, more to do with flow.
‘‘We took these guys and put them into the equivalent of a treadmill for fish which allowed us to quantify their swimming ability and found the swimming behaviour of six species varied significantly.
‘‘One species was the worst swimmer in the world and the fish that were really good swimmers were found in really high flow areas.
‘‘We recorded them swimming up to 1.9 metres per second in Emmagen Creek - these fish are only 10cm long.
‘‘The reason why they are able to exist in high flowing environments is because of a suction cap on the underside of their body used to grip onto rocks.’’
The orange-mouthed goby found in the creeks was discovered over 10 years ago but it has not yet been formally described.
‘‘A lot of these gobies have only been recently discovered in Australia in the past three or four years and the rabbit-headed goby is more or less found just in the Wet Tropics and elsewhere across the Pacific,’’ Mr Donaldson said.
‘‘No one has done similar work to see if these patterns exist through other areas in the Pacific.
‘‘By basing our studies on snorkelling in the streams, we found our technique turned up new species which was better than previous tests using electro-pulse fishing.’’
researchers Dr. Brendan Ebner and James Donalson on the job in the Daintree rainforest