Snorkelling boffins’ fishy find

Port Douglas & Mossman Gazette - - FRONT PAGE - Angelique Pat­ter­son

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.’’

SNORKELLING SCI­EN­TISTS:

re­searchers Dr. Bren­dan Eb­ner and James Don­al­son on the job in the Dain­tree rain­for­est

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