Jun 052014
The platypus is vulnerable to opera house traps set to catch crayfish.

The platypus is vulnerable to opera house traps set to catch crayfish.

Original story at Wildlife Extra

The Australian Platypus Conservancy (APC) has been carrying out trials on a new design of a type of crayfish trap called an opera house trap. Opera house traps are widely sold in Australia to deploy in rivers to catch crayfish for eating. Unfortunately, these same rivers are populated by air-breathing platypus that cannot escape from the traps once they have entered them and so drown. The new design is fitted with a circular escape hatch in the roof, through which platypus can find their way back out. The research, funded by the Taronga Conservation Society, involved 34 adults and 24 juvenile platypus to establish how easily the animals found the escape holes.

Of the four animals tested during daylight hours, all escaped within one minute of being introduced to a trap. At night, 63 per cent of tested animals managed to find their own way out within one minute and 19 per cent in 1-2 minutes. All exited via the escape hatch in the roof. Given that a platypus can hold its breath for approximately two and a half minutes when active, these findings suggest that a large proportion of wild platypus are likely to escape from a modified trap before they drown.

APC believes that to ensure that crayfish catching practices are both ethical and environmentally sustainable, opera house traps should clearly not be set in water bodies where platypus regularly occur, even if the traps are fitted with escape hatches. Traps can lawfully be set only in private farm dams and the like.

However, given the very large numbers of opera house traps purchased annually across the platypus’s range, it is inevitable that some will be deployed in rivers and streams supporting platypus, even in places where such use is banned. Although opera house traps fitted with an escape hatch are not completely platypus-safe, they certainly present less risk to animals than the standard design.

Accordingly, APC advocates that sale of standard opera house traps should be universally phased out as soon as possible. This change is also likely to assist conservation of freshwater turtles and native Australian water-rats (or rakali), both of which are more likely to inhabit farm dams than are platypus.

Studies assessing the ability of turtles to escape from opera house traps fitted with an escape hatch are currently being completed by Turtles Australia in partnership with the APC.

For more information visit www.platypus.asn.au

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