Scientists said on Tuesday that they had discovered the world’s first hybrid sharks in Australian waters, a potential sign the predators were adapting to cope with climate change.
The mating of the local Australian black-tip shark with its global counterpart, the common black-tip, was an unprecedented discovery with implications for the entire shark world, said lead researcher Jess Morgan.
“It’s very surprising because no one’s ever seen shark hybrids before, this is not a common occurrence by any stretch of the imagination,” Morgan, from the University of Queensland, told
“This is evolution in action.”
Colin Simpfendorfer, a partner in Morgan’s research from James Cook University, said initial studies suggested the hybrid species was relatively robust, with a number of generations discovered across 57 specimens.
The find was made during cataloguing work off Australia’s east coast when Morgan said genetic testing showed certain sharks to be one species when physically they looked to be another.
The Australian black-tip is slightly smaller than its common cousin and can only live in tropical waters, but its hybrid offspring have been found 2,000 kilometres down the coast, in cooler seas.
“Hybridization could enable the sharks to adapt to environmental change as the smaller Australian black tip currently favours tropical waters in the north while the larger common black tip is more abundant in sub-tropical and temperate waters along the south-eastern Australian coastline.”
It means the Australian black-tip could be adapting to ensure its survival as sea temperatures change because of global warming.
“If it hybridises with the common species it can effectively shift its range further south into cooler waters, so the effect of this hybridising is a range expansion,” Morgan said.
“It’s enabled a species restricted to the tropics to move into temperate waters.”
Climate change and human fishing are some of the potential triggers being investigated by the team, with further genetic mapping also planned to examine whether it was an ancient process just discovered or a more recent phenomenon.
If the hybrid was found to be stronger than its parent species — a literal survival of the fittest — Simpfen dorfer said it may eventually outlast its so-called pure-bred predecessors.
“We don’t know whether that’s the case here, but certainly we know that they are viable, they reproduce and that there are multiple generations of hybrids now that we can see from the genetic road map that we’ve generated from these animals,” he said.
“Certainly it appears that they are fairly fit individuals.”
The hybrids were extraordinarily abundant, accounting for up to 20 percent of black-tip populations in some areas, but Morgan said that didn’t appear to be at the expense of their single-breed parents, adding to the mystery.
The findings of a new hybrid species of shark goes to show just how versatile life can be in dealing with the ecosystem altering forces of climate change,proving yet again that within the depths of the world’s oceans and its most keenly adapted inhabitants, there may be no shortage of natural marvels and awesome phenomena left to be discovered.