Hybrid Shark Found off Australian Coast

 

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. This is not a common occurrence by any stretch of the imagination; 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. 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 — it may eventually outlast its so-called pure-bred predecessors.

Hybrid sharks are viable, they reproduce and that there are multiple generations of hybrids now that we can see from the genetic roadmap generated from these animals. Certainly it appears that they are fairly fit individuals. The hybrids were extraorindarily abundant, accounting for up to 20 percent of black-tip populations in some areas, but that didn’t appear to be at the expense of their single-breed parents, adding to the mystery.