Shark population have been declining steady around the human beings for decades . It feels like every other hebdomad ashocking new reportreveals the dire straits of these vulnerable creatures . This time it is the turn of the vertex predators of Australia ’s east coast , whose numbers have plummeted alarmingly in the last half a C .
Anew studyhas revealed that the numbers of iconic coinage such as hammerheads , Panthera tigris shark , and keen whites that live in the water supply off the sea-coast of Queensland have omit by as much as 92 percentage in just 50 years .
Researchers from the University of Queensland ( UQ ) used data from a shark control program , which was first prompt to minimize shark - human interactions in 1962 , that now load over 1,100 nautical mile ( 1,760 kilometre ) and includes the Great Barrier Reef .
Before that there are no official records , so researchers have used the shark control data point to construct historical criminal record of shark numbers and shark haul over the last half a century to understand the changes that have study plaza between then and now .
“ Explorers in the 19th century once described Australian coastlines as being ‘ chock - full of shark , ’ yet we do n’t have a percipient idea of how many sharks there used to be on Queensland beach , ” Dr George Roff of UQ , who conduct the study , explain in astatement .
“ We will never know the exact turn of shark in our ocean more than half a one C ago , but the data points to radical modification in our coastal ecosystems since the 1960s . ”
The shark control program utilize baited drumlines to bring down local population , hit shark encounters with human being less likely . According to the study , bring out inCommunications Biology , nearly 50,000 sharks have been caught by this method acting . Though the cooking stove of species caught has been diverse , proper metal money recognition in the recording only began in the 1990s , so the earliest records aggroup them all into five categories : hammerheads , tigers sharks , great White , whaling ship shark , and “ other ” .
“ What we regain is that large apex shark such as hammerheads , tigers and white shark , have declined by 74 to 92 percent along Queensland ’s coast , ” Dr Roff say .
“ And the chance of zero catch – catching no sharks at any given beach per class – has increase by as much as seven - sheepcote . ”
That ’s not all . The decennium of data point uncover another drift , most likely a result of few sharks reaching generative age .
“ The mean sizing of shark has also worsen – Panthera tigris sharks and hammerhead shark sharks are get humble , ” Roff said .
While human - shark interaction are not desirable , it ’s the shark that usually arrive off worst . Around100 million sharksare killed each class globally by homo , while shark kill on averagesix humansa year .
However , the research worker reason that while the shark ascendency plan certainly contribute to the diminishing numbers , the probable culprit is commercial-grade sportfishing , both for the Asian marketplace and as by-catch thanks to big fishing nets .
