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Tiger Shark Monogamy Fuels Sustainability Risk

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Tiger sharks appear to be genetically monogamous, and it could be putting the species at risk. A study published in Royal Society Open Science has found that tiger sharks differ from many other sharks in that they don’t use multiple paternity as a reproductive strategy.

Multiple paternity occurs when a single litter of offspring is fertilised by several males so that pups from the same brood have different fathers. This may ultimately increase the genetic diversity of a species.

Multiple paternity was previously believed to be a widespread reproductive strategy among sharks, with half-siblings born at the same time.

“The DNA of 112 tiger shark pups from Cairns, Rainbow Beach and the Gold Coast was tested to see if they had different fathers,” said Dr Bonnie Holmes of the University of Queensland. “Surprisingly, all pups in each litter appeared to have the same father, except one.”

Holmes said this provided critical information for managing the sustainability of tiger sharks globally. “It is the first genetic assessment of the reproductive strategy of these sharks,” she said.

“On the Australian east coast, the species is targeted heavily in shark control operations, recreational game fishing activities and commercial fishing operations. Tiger sharks in this region may have a reduced capacity to withstand significant fishing pressure,...

The full text of this article can be purchased from Informit.