Hybrid Shark Discovered in Australia
Filed Under: Health & Science, World | Posted: 01/04/2012 at 10:20PM
Comments | Region: Australia
Scientists in Australia found hybrids and ensure that sharks could be an indication of how marine predators are adapting to climate change.
"This is very surprising. No one had ever seen hybrid shark," said Jess Morgan, University of Queensland, principal investigator of the group that made the discovery.
The 57 animals found are the result of mating two different species, the blacktip shark Australian Australian blacktip shark(Carcharhinus Tilston) blacktip shark and blacktip shark or common Common blacktip shark (Carcharhinus limbatus).
Both species are very similar and it is very difficult to distinguish at a glance.
Evolution in action
The sharks were discovered during a project to catalog marine species in the east coast of Australia. Morgan pointed out that genetic testing confirmed that it is indeed a new species.
The Australian blacktip shark is slightly smaller than blacktip shark and can only live in tropical waters. But the shark hybrid was found at a distance of about 2000 kilometers to the south in much colder waters.
This means that the Australian blacktip shark may be trying to ensure their survival and continued in future generations to changes in temperature due to climate change.
"If the Australian blacktip shark is paired with the common blacktip shark, their offspring may live much further south in cold water," said Morgan.
"Mating with another species you expand your range of habitat. A species restricted to the tropics may well move to warmer waters. What we’re seeing is evolution in action."
Addition to climate change, one of the factors studied as a possible cause of the unusual mating is overfishing. Scientists also hope to determine whether it is a new phenomenon or a change that you have some time but recently has been discovered.
If sharks hybrids prove more robust than their parents, in an example of survival of the fittest, the new species could end up going eventually to their predecessors.
"We know that with certainty, but we do know that sharks hybrids are viable and reproduce and that there are already multiple generations of hybrids," said Colin Simpfendorfer of James Cook University, another of the researchers.
The hybrids do not seem to have affected the size of the progenitor populations, which is another mystery to solve, according to Morgan.
For Simpfendorfer, the discovery has important implications for the study of the evolution of sharks.
"We thought we understood how the different species of sharks had emerged, but what this is telling us is that we still do not fully understand the mechanisms that led to the separation of species."
Morgan believes there could be other hybrid species of sharks off the coast of Autralia.
"We have not examined all the species of sharks on the West Coast and the Northern Territory coast. One of the questions we hope to answer is how widespread is the phenomenon of hybridization."